Thousands of demonstrators from a banned Pakistani Islamist group clashed with police outside Lahore on Wednesday, killing and wounding several, police and the group said, in a row about a French magazine’s cartoons.

The clash broke out at a rally of the banned Tehrik-e-Labaik Pakistan (TLP) on a highway in Sheikhupura, just outside the eastern city of Lahore, a spokesman for the Punjab police said on Wednesday.

“TLP activists used SMG, AK-47s and pistols to target police officials as the result of which several officials were martyred,” the spokesman said.

The interior minister told reporters that three police officers had been killed and 70 wounded, adding that the government had deployed paramilitary troops in the Pakistani province of Punjab to help manage the situation.

“They will be there for 60 days. I have given them authority that they could go to anywhere they want in Punjab,” he told reporters. “I'm still warning the TLP to please back off.”

The group said several of its activists had also been killed or wounded.

This is the group’s third countrywide protest campaign since 2017 over a series of caricatures of the Prophet Mohammad published in the French satirical magazine Charlie Hebdo. Such caricatures are considered deeply insulting by Muslims.

Charlie Hebdo first published the cartoons in 2006 and republished them last year to mark the opening of a trial over a deadly attack on the magazine by Islamist militants in 2015. Pakistani information minister Fawad Chaudhry said the government will use force to block the Islamists from entering the capital Islamabad.

“We have shown restraint so far but the challenge to the state's authority can’t be tolerated any more,” he told reporters.

Thousands of TLP activists have blocked Pakistan’s busiest highway since Friday, demanding the release of their leader and the expulsion of France’s ambassador.

After negotiations with the government failed, the demonstrators began marching towards the capital Islamabad on Wednesday.

Districts along the Grand Trunk Road were brought to a standstill where the city administration had already placed shipping containers to block entry and exit routes.

Police said they had tried to block the march, which triggered the clashes. The highway sit-in followed clashes in Lahore on Friday that killed three police officers.