Six Pakistan MPs from jailed former prime minister Imran Khan's party were among more than 30 people remanded in custody on Tuesday under a new law restricting protests.
It comes after thousands of supporters of Khan's Pakistan Tehreek-e-Insaf (PTI) party gathered in the capital Islamabad on Sunday for a rally that was broken up with tear gas.
The party has faced a sweeping crackdown since former cricket start Khan was jailed in August last year on a series of charges that he says are politically motivated and designed to keep him from power.
The MPs appeared at an anti-terrorism court in Islamabad where a judge remanded them in custody for eight days, an AFP journalist witnessed.
They are accused of violating the Peaceful Assembly and Public Order Act 2024 -- passed just last week -- according to a charge sheet seen by AFP in court.
In total 34 people were named on the charge sheet as having been remanded in custody.
PTI leader and senior lawyer Muhammad Shoaib Shaheen, who appeared in court alongside the MPs, faced a police complaint about an "attack on officials", "armed riots" and "illegal assembly" after Sunday's rally and was also remanded in custody.
"I was picked up from my office around 7:30 pm," he said at the court.
"These small obstacles won't hold us back. We are the soldiers of Imran Khan, and we stand with him," he said.
Several of the group were rounded up by police as they left the National Assembly building in the capital on Monday night, PTI's media team said.
Gohar Ali Khan, PTI chairman in Imran Khan's absence, was also taken away by police but later released, he told reporters.
"These are not the offences where you should charge people with terrorism legislation," he told the media.
- New protest law -
Thousands of Khan supporters turned out for Sunday's rally, the largest in the capital since February elections when rival parties formed a coalition to keep PTI from power, despite the party winning the most seats.
It was the first demonstration since the government passed a new law regulating public gatherings, which it said would allow for peaceful assembly subject to reasonable restrictions.
Political, religious and civil rights groups frequently stage sit-ins and protests in Pakistan that can see cities shut down for days.
However, rights groups say the law is a curb on freedom of expression and it part of a continued crackdown on peaceful protests.
City authorities gave permission for the demonstration to go ahead but it continued beyond the stipulated time and authorities used to tear gas to disperse crowds.
Authorities had earlier warned of legal action "for violation of the permission".
Imran Khan rose to power in 2018 with the help of the military, analysts say, but was ousted in 2022 after reportedly falling out with the generals.
A United Nations panel of experts found this month that his detention "had no legal basis and appears to have been intended to disqualify him from running for political office".
Several convictions against him have been overturned by the courts.
Several members of the PTI's social media and press team were rounded up last month and accused of "anti-state propaganda".