Pakistan’s former prime minister Imran Khan has been arrested outside the High Court in the capital, Islamabad.
Mr Khan was appearing in court on charges of corruption, which he says are politically motivated.
Footage showed dozens of paramilitary forces in armoured vehicles detaining Mr Khan after he entered the court compound, then driving him away.
He was ousted as PM in April last year and has been campaigning for early elections since then.
General elections are due to be held later this year.
Mr Khan’s Pakistan Tehreek-e-Insaf (PTI) party has called on its supporters to protest. In the hours since he was detained, violence has been reported from a number of cities including Lahore, Karachi and Peshawar.
On the streets of Islamabad, hundreds of protesters blocked one of the main highways in and out of the capital.
People pulled down street signs and parts of overpasses, lit fires and threw stones. During the hour or so that the BBC was there, no police or authorities were visible.
Protesters said they were angry about Imran Khan’s arrest.
“This is absolutely the last straw,” said Farida Roedad.
“What else can we do? What else is there left in Pakistan? We have never said a word against the army, I wish we had.
“Let there be anarchy, let there be chaos. If there is no Imran, there’s nothing left in Pakistan. No one is there to take over.”
Writing on social media, police in Islamabad said five police officers had been injured and 43 protesters arrested.
Footage from Lahore posted on Twitter appeared to show crowds breaking into the military corps commander’s house, destroying furniture and belongings inside.
Protesters in the main port city of Karachi have been blocking a main road, Reuters reported.
It said at least 10 people, including six police officers, had been injured in the south-western city of Quetta in clashes with Mr Khan’s supporters.
(BBC News)