The search for survivors of the earthquake that toppled thousands of buildings in Turkey and Syria reached a critical stretch on Wednesday, with rescue teams from two dozen countries helping locals sift through the rubble and experts warning that the realistic window to find any in the frigid temperatures was quickly closing.

The death toll from the magnitude 7.8 quake that struck Monday (Feb. 6) crossed 20,000 by Thursday, making it the deadliest natural disaster to hit the planet since the December 2004 Indian Ocean earthquake and tsunami.

Nearly all of Turkey is very seismically active so the country is no stranger to devastating earthquakes - a 7.4 magnitude tremor that struck near Istanbul in 1999 killed an estimated 18,000 people.

With the damage from Monday's quake so extensive and spread so widely, experts said the window for survival was quickly closing, though people can survive for up to a week or more, depending on the circumstances.

The extent of the devastation was breathtaking, with rows of apartment blocks reduced to twisted metal, rubble and dust in many communities. Rescuers formed human chains as they tried to dig through collapsed buildings, urging quiet every so often in the hopes of hearing stifled pleas for help.

Glimpses of Hope

The overwhelming sadness has given way to moments of muted joy. In the town of Jinderis in northwestern Syria, where 12 years of conflict has complicated rescue efforts, residents digging through a collapsed building Monday afternoon discovered a crying infant whose mother appears to have given birth to her while buried in the rubble. The girl's mother, father and four siblings didn't survive. Rescuers pulled another little girl from the wreckage of a collapsed building in the same town that evening.

Former Chelsea and Newcastle forward Christian Atsu was rescued from the ruins of a collapsed building in the southern Turkey city of Antakya, where his current team, Hatayspor, is based, the Ghana Football Association tweeted Tuesday.

In the southern Turkey city of Kahramanmaras, Mufit Hisir told The Associated Press that rescuers pulled his mother and brother alive from the rubble after digging for hours.

Many whose homes were damaged or destroyed expressed frustration at the Turkish government response, having to sleep in cars, shelters or outside in subfreezing temperatures.

"We don't have a tent, we don't have a heating stove, we don't have anything. Our children are in bad shape. We are all getting wet under the rain and our kids are out in the cold," Aysan Kurt, 27, told the AP. "We did not die from hunger or the earthquake, but we will die freezing from the cold. It shouldn't be this way. No one is sending help."

Turkish President Recep Tayyip Erdogan visited the especially hard-hit Hatay province, where more than 3,300 people died and entire neighbourhoods were destroyed. Residents there have accused the government of being slow to send help.

Erdogan, who faces a tough battle for reelection in May, acknowledged "shortcomings" in the response but said the weather had been a factor. The earthquake destroyed the runway in Hatay's airport, further disrupting the response.

He also hit back at critics, saying "dishonourable people" were spreading "lies and slander" about the government's response.

Turkish authorities said they were targeting disinformation, and an internet monitoring group said access to Twitter was restricted despite it being used by survivors to alert rescuers.

Offers of Aid

Crews from at least 24 countries, including those at odds over the war in Ukraine, are taking part in the rescue operation.

Among the countries helping is Turkey's neighbour and historic rival Greece, which is sending Turkey a team of 21 rescuers, two rescue dogs and a special rescue vehicle, together with a structural engineer, five doctors and seismic planning experts in a military transport plane.

And aid groups including the International Committee of the Red Cross are sending assistance, including medical equipment, food, blankets, mattresses and other essential items.

Quake rescue effort goes global

Medical personnel, soldiers, and handlers with trained search dogs sent from around the world are arriving in Turkey and Syria to help rescue survivors. Here's a glance at the assistance being provided:

- The European Union has mobilised search and rescue teams to help Turkey, while the bloc's Copernicus satellite system has been activated to provide emergency mapping services. At least 19 member countries have offered assistance. The European Commission is also helping neighbouring Syria by funding humanitarian organisations supervising search and rescue operations.

- The United States is coordinating immediate assistance to Turkey, including teams to support search and rescue efforts. In California, nearly 100 Los Angeles County firefighters and structural engineers, along with six specially trained dogs, were being sent to Turkey.

- War-ravaged Syria called for the United Nations and its members to help with rescue efforts, health services, shelter and food aid. Both government-held territory and the last opposition-held enclave were damaged by the earthquake.

- The International Committee of the Red Cross has sent enough surgical material to treat 100 people to one of the public hospitals in the Syrian city of Aleppo. More medical equipment is on its way to Aleppo, Latakia and Tartous. The Red Cross also is donating canned food, blankets, mattresses and other essential items for distribution in the many shelters being set-up in affected areas.

- Russian rescue teams from the Emergencies Ministry were sent to Syria, where Russian military deployed in that country already has sent 10 units comprising 300 people to help clear debris and search for survivors. The Russian military has set up points to distribute humanitarian assistance. Russia also has offered help to Turkey, which has been accepted.

- The Israeli army is sending a search and rescue team of 150 engineers, medical personnel and other aid workers to render lifesaving aid in Turkey. The two countries are mending ties after years of tensions. Prime Minister Benjamin Netanyahu said he has also approved a request for humanitarian aid for Syria. Israel and Syria do not have diplomatic relations.

- A team of 82 rescuers sent by the Chinese government has arrived in Adana, Turkey. They include specialists in search and rescue as well as medical treatment, and they brought in 21 tons of rescue equipment and supplies. China's CCTV also said a non-governmental rescue and search organisation from Zhejiang province also sent an advanced team to Turkey.

- Palestinian Foreign Minister Riad Malki said the Palestinian Authority will dispatch two humanitarian missions to assist in Syria and Turkey. The aid missions will include civil defence and medical teams.

- Neighbour and historic rival Greece is sending Turkey a team of 21 rescuers, two rescue dogs and a special rescue vehicle, together with a structural engineer, five doctors and seismic planning experts in a military transport plane.

- The Lebanese army says it will send a team of 15 members of the military's engineering regiment to neighbouring Syria to help in rescue operations in government-held parts of the country. Tuesday's announcement came a day after the army sent 20 members of the same regiment to Turkey to help rescuers there who are racing to find survivors.

- One of Libya's rival governments said it will dispatch a 55-member team to Turkey to help in rescue efforts. The government of Prime Minister Abdel Hamid Dbeibah said the team would include rescuers, medical members along with four dogs.

- Spanish medical workers will set up a field hospital in Turkey to treat the wounded. Spain has mobilised troops and drones from the country's Military Emergency Unit to Malatya airport, where the Turkish authorities have installed an international aid centre. Spain will also contribute to aid efforts through the International Federation of Red Cross and Red Crescent Societies. Spain will also contribute to rescue efforts in Syria through NGOs operating there.

- Germany's THW civil protection agency is sending a 50-member rescue team to Turkey on Tuesday. A team from the group International Search and Rescue Germany, with 42 experts and seven dogs, has arrived in Turkey and is heading to Kirikhan, near the Syrian border. Germany also has been readying deliveries of emergency generators, tents, blankets and water treatment equipment.

- A South Korean disaster relief team of 110 rescue workers and medical supplies have arrived at Gaziantep airport in Turkey. The Foreign Ministry says the team includes 60 civilian rescuers and 50 military personnel.

- Australia's government will be sending up to 72 personnel capable of finding and removing trapped people and delivering medical aid.

- Pakistan has sent one flight of relief supplies and another carrying a 50-member search and rescue team. The government says daily aid flights to Syria and Turkey will start Wednesday, and Prime Minister Shehbaz Sharif set up a relief fund, urging people to donate generously. The federal cabinet is donating a month's salary and all government employees are donating a day's salary toward it.

- Britain is sending 76 search-and-rescue specialists with equipment and dogs, as well as an emergency medical team, to Turkey. The U.K. also says it's in contact with the U.N. about getting support to victims in Syria.

- India is sending 100 search and rescue personnel from its Natural Disaster Response Force to Turkey, as well as specially trained dog squads and equipment for relief efforts. Medical teams with trained doctors, paramedics and essential medicines are also ready, the Ministry of External Affairs said in a statement.

- Taiwan is sending 130 rescue squad members, five search dogs and 13 tons of equipment to Turkey. Interior Minister Lin Yu-chang said the first group left for Turkey late Monday and another was sent Tuesday. Taiwan earlier said it would donate $200,000 to Turkey.

- Swiss rescue dog service REDOG is sending 22 rescuers with 14 dogs to Turkey. The government said it would also send 80 search and rescue specialists to the country, including army disaster experts.

- The Czech Republic is sending Turkey a team of 68 rescuers, including firefighters, doctors, structural engineers and also experts with sniffer dogs.

- Japan has sent two teams of rescuers to Turkey. The first group left Monday and the second, with more than 50 members and five dogs, left Tuesday evening.

- Austria has offered to send 84 soldiers from a military disaster relief unit to Turkey.

- Poland is sending Turkey 76 firefighters and eight trained dogs, with equipment.

- Romania is sending specialised personnel and material to Turkey on two military aircraft.

- Croatia is sending 40 personnel and 10 dogs, rescue equipment and vans to Turkey.

- Serbia is sending 21 rescuers and three liaison officers to Turkey.

- Montenegro is sending at least 24 firefighters to Turkey.

- Moldova's president says 55 rescue workers have been sent to Turkey.

- France is dispatching rescue teams to Turkey.

- Jordan is sending emergency aid to Syria and Turkey on the orders of King Abdullah II.

- Mexico's foreign affairs secretary said the country will send equipment and rescue specialists to Turkey.

- Egypt has pledged urgent humanitarian aid to Turkey.

- Italy's Civil Protection Agency has offered assistance to Turkey. A firefighting team was preparing to leave from Pisa, and the Italian military says transport flights will carry equipment as well as health and other personnel.

- New Zealand is providing $632,000 to the Turkish Red Crescent and $316,000 to the Syrian Arab Red Crescent to deliver items such as food, tents and blankets, as well as provide medical assistance and psychological support.

- China's Red Cross Society is providing the Turkish Red Crescent and the Syrian Red Crescent with $200,000 each in humanitarian assistance.

- Albania and Kosovo have sent emergency teams to Turkey to assist in search and rescue. Albania's 53-member team consists of firefighters and army and health personnel.

- Finland will send 1 million euros in humanitarian assistance to Turkey and Syria through the International Federation of Red Cross and Red Crescent Societies. The support will be used to provide food, shelter, medical supplies and psychosocial support to people who lost their homes.

- Greece's Orthodox Church has announced a charity drive and prayer services in support of victims.

Deadliest quakes if the last 25 years

A magnitude 7.8 earthquake shook Turkey and Syria on Monday, killing thousands of people in the two countries. The death toll is expected to rise as rescuers working in cold and snow look for trapped people in the rubble of toppled buildings.

Here are some of the world's deadliest earthquakes in the past 25 years:

- June 22, 2022: In Afghanistan, more than 1,100 people die in magnitude 6.1 earthquake.

- Aug. 14, 2021: In Haiti, a magnitude 7.2 earthquake kills more than 2,200 people.

- Sept. 28, 2018: A magnitude 7.5 earthquake hits Indonesia, triggering a tsunami and killing more than 4,300 people.

- April 25, 2015: In Nepal, more than 8,800 people are killed by a magnitude 7.8 earthquake.

- March 11, 2011: A magnitude 9.0 quake off the northeast coast of Japan triggers a tsunami, killing nearly 20,000 people.

- Jan. 12, 2010: In Haiti, over 100,000 people are killed by a magnitude 7.0 quake. Government estimates put the number at a staggering 316,000 dead.

- May 12, 2008: A magnitude 7.9 quake strikes eastern Sichuan in China, resulting in over 87,500 deaths.

- May 27, 2006: More than 5,700 people die when a magnitude 6.3 quake hits the island of Java, Indonesia.

- Oct. 8, 2005: A magnitude 7.6 earthquake kills over 80,000 people in Pakistan's Kashmir region.

- March 28, 2005: A magnitude 8.6 quake in northern Sumatra in Indonesia kills about 1,300 people.

- Dec. 26, 2004: A magnitude 9.1 quake in Indonesia triggers an Indian Ocean tsunami, killing about 230,000 people in a dozen countries.

- Dec. 26, 2003: A magnitude 6.6 earthquake hits southeastern Iran, resulting in more than 20,000 deaths.

- May 21, 2003: More than 2,200 people are killed in a magnitude 6.8 earthquake in Algeria.

- Jan. 26, 2001: A magnitude 7.6 quake strikes Gujarat in India, killing as many as 20,000 people.

- Aug. 17, 1999: A magnitude 7.6 earthquake hits Izmit, Turkey, killing about 18,000 people.

- May 30, 1998: Over 4,000 people are killed after a 6.6 magnitude temblor hits Afghanistan's Badakhshan province.