A radical Islamist party on Saturday said five of its supporters have died in clashes with authorities in Pakistan's eastern city of Lahore, after two police officers were killed in the unrest.
On Friday more than 1,000 people from Tehreek-e-Labbaik Pakistan (TLP) gathered after prayers to demand the release of their detained leader, blocking roads and firing projectiles.
The protests continued on Saturday.
The TLP has previously been behind major anti-France protests that earlier this year led to the embassy issuing a warning for all French citizens to leave the country.
"Tehreek-e-Labbaik Pakistan lost two people Friday night and three more today to police firing," the party tweeted on Saturday.
Police in Lahore would not comment on the claim, but on Friday night said two of its officers had died.
"The clashes are still ongoing," Rana Arif, a spokesman for Lahore police, told AFP.
"This is a defensive operation by police against the mob... We are only doing shelling to control the crowd."
TLP leader Saad Rizvi was arrested in April when Pakistan's government outlawed the party in response to violent anti-France protests.
Supporters have threatened to move in convoys towards the capital Islamabad, where police have closed off roads using shipping containers.
The party has vowed not to end the protests or enter talks with the government until their leader is released.
Interior minister Sheikh Rashid Ahmad, who had been in Dubai to watch Pakistan compete in the T20 cricket World Cup, returned home on Prime Minister Imran Khan's directive to monitor the situation.
The TLP has waged an anti-France campaign since President Emmanuel Macron defended the right of a satirical magazine to republish cartoons depicting the Prophet Mohammed -- an act deemed blasphemous by many Muslims.
Six police officers were killed in April when the TLP staged days of rallies which paralysed roads.
Few issues are as galvanising in Pakistan as blasphemy, and even the slightest suggestion of an insult to Islam can supercharge protests, incite lynchings, and unite most of the country's warring political parties.