With former Prime Minister Imran Khan in custody, Pakistani authorities on Thursday cracked down on his supporters, arresting hundreds in overnight raids and sending troops across the country to rein in the wave of violence that followed his arrest earlier this week.

For this Islamic nation, accustomed to military takeovers, political crises and violence, the turmoil has been unprecedented. It echoed unrest that followed the 2007 assassination of former Prime Minister Benazir Bhutto during an election rally in the garrison city of Rawalpindi. Her supporters at the time, outraged by her killing, rampaged for days across Pakistan.

Clashes with police since Khan's dramatic arrest on Tuesday have killed at least eight of his supporters and dozens have been injured. Five of the deaths were reported in northwestern Khyber Pakhtunkhwa province, two in the eastern city of Lahore and one person was killed in the southwestern city of Quetta. More than 200 police officers were also injured. The demonstrators burned down a railway station on the outskirts of the capital, Islamabad, on Wednesday night.

Police said Thursday that nearly 1,600 of Khan supporters were arrested overnight on charges of damaging public property and attacking military installations. In one incident - hours after Khan's arrest - a mob set fire Tuesday to the sprawling residence of a top army commander in the eastern city of Lahore. Some 2,000 of Khan's supporters were arrested earlier on Wednesday and Tuesday.

Khan was dragged from a courtroom in Islamabad where he showed up to face graft charges on Tuesday. He is now being held at a police compound in Islamabad where, at a temporary court set up there, a judge on Wednesday ordered the 70-year-old opposition leader detained for at least another eight days, raising the prospect of more unrest.

Also Thursday, police filed new terrorism charges against Khan and top leaders from his Pakistan Tehreek-e-Insaf party on charges of inciting mobs to violence. They said the mobs attacked military installations, damaged public property, burned down dozens of police vehicles, attacked police officers and disrupted life by blocking key roads and highways.

In an address to the nation late Wednesday, Prime Minister Shahbaz Sharif - who took over after Khan was ousted in April last year in a no-confidence vote in Parliament - said the unrest by the followers of the former premier had "damaged sensitive public and private property," forcing him to deploy the military in Islamabad, the most populous province of Punjab and in volatile regions of the northwest.

"Such scenes were never seen by the people of Pakistan," Sharif said, following a Cabinet meeting. "Even patients were taken out of ambulances and ambulances were set on fire."

Sharif called the attacks "unforgivable," and warned that those involved in violence would be given exemplary punishment. He said Khan was arrested because of his involvement in corruption, and that there was evidence available to back up these charges.

Foreign Minister Bilawal Bhutto Zardari, who is the late Benazir Bhutto's son, urged Khan's followers on Thursday to end the violence but stressed that peaceful protests are their right. "What has happened, has happened. Don't make things more difficult for yourself," he said.

Following the violence, the government has shut down schools, colleges and universities in the eastern Punjab and northwestern Khyber Pakhtunkhwa provinces, where Khan has a massive grassroot following and from where most of the violence was reported after his arrest. The government also suspended internet service in various parts of the country.

The government blames Khan and senior leaders from his Pakistan Tehreek-e-Insaf party of inciting people to violence, which continued Thursday in Punjab and in the northwest.

On Wednesday, a court in Islamabad decided that the National Accountability Bureau can hold Khan in its custody for eight days for questioning over a graft case.

The military headquarters in the garrison city of Rawalpindi was attacked and Khan's supporters stormed security posts in the northwest, torching the security Chakdara fort on the border with Afghanistan. In Lahore on Tuesday night, demonstrators ransacked and then burned down the residence of the top regional commander in Lahore, Lt. Gen. Salman Fayyaz Ghani.

"We will arrest all those who disrupted law and order," said Mohson Naqvi, the chief minister in Punjab.

Officials say Khan's supporters in particular targeted military installations because he has been blaming the military for his 2022 ouster, while also claiming it was a conspiracy by Washington and Sharif's government - charges that both the United States and Khan's successor have denied. The military has also said it played no role in Khan's ouster.

The military on Wednesday issued a strongly worded statement, vowing to respond to attacks by demonstrators with full force. It said the attacks on its installations were launched in an orchestrated manner, and the violence was a "black chapter" in the country's history.

The military has directly ruled Pakistan for more than half of the 75 years since the country gained independence from British colonial rule, and wields considerable power over civilian governments.

From The Associated Press