A powerful explosion apparently caused by a natural gas leak killed at least 22 people, including a child, and injured dozens Friday when it blew away outer walls from a luxury hotel in the heart of Cuba's capital.

No tourists were staying at Havana's 96-room Hotel Saratoga because it was undergoing renovations, Havana Gov. Reinaldo García Zapata told the Communist Party newspaper Granma.

"It's not a bomb or an attack. It is a tragic accident," President Miguel Díaz-Canel, who visited the site, said in a tweet.

Dr. Julio Guerra Izquierdo, chief of hospital services at the Ministry of Health, told reporters that at least 74 people had been injured. Among them were 14 children, according to a tweet from Díaz-Canel's office.

Díaz-Canel said families in buildings near the hotel affected by the explosion had been transferred to safer locations.

Cuban state TV reported the explosion was caused by a truck that had been supplying natural gas to the hotel, but did not provide details on how the gas ignited. A white tanker truck was seen being removed from the site as rescue workers hosed it down with water.

Tourism Minister Juan Carlos García said the hotel was scheduled to reopen Tuesday.

The blast sent smoke billowing into the air around the hotel with people on the street staring in awe, one saying "Oh my God," and cars honking their horns as they sped away from the scene, video showed. It happened as Cuba is struggling to revive its key tourism sector that was devastated by the coronavirus pandemic.

Cuba's national health minister, José Ángel Portal, told The Associated Press the number of injured could rise as the search continues for people who may be trapped in the rubble of the 19th century structure in the Old Havana neighborhood of the city.

"We are still looking for a large group of people who may be under the rubble," Lt. Col. Noel Silva of the Fire Department said.

A 300-student school next to the hotel was evacuated. García Zapata said five of the students suffered minor injuries.

Police cordoned off the area as firefighters and rescue workers toiled inside the wreckage of the emblematic hotel about 110 yards (100 meters) from Cuba's Capitol building.

The hotel was first renovated in 2005 as part of the Cuban government's revival of Old Havana and is owned by the Cuban military's tourism business arm, Grupo de Turismo Gaviota SA. The company said it was investigating the cause of the blast and did not immediately respond to an email seeking more details about the hotel and the renovation it was undergoing.

The Hotel Saratoga has been used frequently by visiting VIPs and political figures, including high-ranking U.S. government delegations. Beyoncé and Jay-Z stayed there during a 2013 visit to Cuba.

Photographer Michel Figueroa said he was walking past the hotel when "the explosion threw me to the ground, and my head still hurts.... Everything was very fast."

Worried relatives of people who had been working at the hotel showed up at a hospital in the afternoon to look for them. Among them was Beatriz Céspedes Cobas, who was tearfully searching for her sister.

"She had to work today. She is a housekeeper," she said. "I work two blocks away. I felt the noise, and at first, I didn't even associate" the explosion with the hotel.

Yazira de la Caridad said the explosion shook her home a block from the hotel: "The whole building moved. I thought it was an earthquake."

Besides the pandemic's impact on Cuba's tourism sector, the country was already struggling with the sanctions imposed by the former U.S. President Donald Trump that have been kept in place the Biden administration. The sanctions limited visits by U.S. tourists to the islands and restricted remittances from Cubans in the U.S. to their families in Cuba.

Tourism had started to revive somewhat early this year, but the war in Ukraine crimped a boom of Russian visitors, who accounted for almost a third of the tourists arriving in Cuba last year.

The explosion happened as Cuba's government hosted the final day of a tourism convention in the iconic beach town of Varadero aimed at drawing investors.

Mexican President Andrés Manuel López Obrador is scheduled to arrive in Havana for a visit late Saturday and Mexican Foreign Relations Secretary Marcelo Ebrard said the visit would still take place.

García Zapata said structures adjacent to the hotel were being evaluated, including two badly damaged apartment buildings. The neighboring Martí Theater, the Yoruba Association and the Capitol had broken glass and damaged masonry.

Mayiee Pérez said she rushed to the hotel after receiving a call from her husband, Daniel Serra, who works at a foreign exchange shop inside the hotel.

She said he told her: "I am fine, I am fine. They got us out." But she was unable to reach him after that.

From The Associated Press