Former Pakistani Prime Minister Imran Khan can be held for questioning for eight days, a court ruled Wednesday, a day after the country’s popular opposition leader was dragged from a courtroom and arrested.

His detention set off clashes between his supporters and police Tuesday, leaving at least four people dead. On Wednesday, angry protesters stormed and set fire to a building housing Radio Pakistan in the northwest.

The 70-year-old politician lost power last year but remains the country’s most popular opposition figure. He is the seventh former prime minister to be arrested in Pakistan. His dramatic arrest on Tuesday deepened the political turmoil.

Two people were killed first, one Tuesday in the southwestern city of Quetta and another in the northwestern city of Peshawar overnight. Two more were in clashes with police Wednesday in Peshawar.

In eastern Punjab province, where authorities said 157 police officers were injured in clashes with Khan supporters, the local government asked the army to step in and restore order.

Pakistan’s GEO television broadcast footage showing Khan appearing before a judge at a temporary court inside a police compound Wednesday. The former premier was seen seated in a chair, holding documents. He appeared calm but tired.

Earlier, the National Accountability Bureau requested 14-day detention of Khan, but the tribunal said authorities could keep him in their custody for eight days.

Meanwhile, Khan’s legal team challenged his arrest before the Islamabad High Court, seeking his release.

Also in Peshawar, Khan’s supporters raided the building housing Radio Pakistan, damaging equipment and setting fire to it, said police official Naeem Khan. Some of the employees were trapped inside, he said, and police were trying to restore order.

Khan’s Pakistan Tehreek-e-Insaf party had called for demonstrators to remain peaceful, hours after mobs angered over the dramatic arrest set fire to the residence of a top army general in the eastern city of Lahore.

When he was arrested on Tuesday, Khan was appearing in court on multiple graft charges brought by Islamabad police. As he showed up in court, dozens of agents from the National Accountability Bureau backed by paramilitary troops stormed the courtroom, breaking windows after Khan’s guards refused to open the door.

Khan’s supporters attacked the military’s headquarters in the garrison city of Rawalpindi near the capital, Islamabad, but did not reach the main building housing the offices of army chief Gen. Asim Munir.

Other demonstrators tried to reach the prime minister’s residence in Lahore, but were driven off by baton-wielding in police. Others attacked vehicles carrying troops and hit armed soldiers with sticks. So far, police and soldiers have not fired at protesters.

The military has not commented on the attacks on its facilities. None of the leaders from Khan’s party denounced the attacks on the military.

A police statement Wednesday said officers in eastern Punjab province arrested 945 Khan supporters since Tuesday — including Asad Umar, a senior leader from Khan’s party. Dozens of Khan supporters were also detained in Islamabad, Karachi, Peshawar and elsewhere.

Shah Mahmood Qureshi, senior vice president from Khan’s party, appealed for peaceful demonstrations Wednesday, urging followers: “Don’t damage public property, don’t attack offices, as we are peace lovers.” He said the party is considering challenging Khan’s arrest in the Supreme Court.

By morning, police said some 2,000 protesters still surrounded the fire-damaged residence in Lahore of Lt. Gen. Salman Fayyaz Ghani, a top regional commander. They chanted slogans at the military, including “Khan is our red line and you have crossed it.” Ghani and his family members were moved to a safer place when the mob on Tuesday first attacked their sprawling house.

Police deployed in force across the country, and placed shipping containers on a road leading to the sprawling police compound in Islamabad where Khan is being held and where he appeared before a judge at the temporary court placed there for security reasons, according to the government.