Four police officers were killed and hundreds injured after armed members of a hard-line Islamist group clashed with Pakistani security forces Wednesday near the northeastern city of Lahore during a protest over a French newspaper’s publication of cartoons depicting the prophet Muhammad.

The violence occurred during a demonstration led by the outlawed Islamist group Tehrik-e-Labbaik Pakistan outside the capital city of Punjab province, as they prepared to march on the national capital, Islamabad. More than 250 people were injured in the clash, according to Usman Buzdar, chief minister of Punjab, who vowed “strict action” against those involved in the incident.

The Islamists were armed with automatic weapons and fired directly on security forces attempting to control the crowd, police said.

It is the latest of several deadly protests organized by the group in Pakistan since French President Emmanuel Macron honored a teacher who was beheaded last year in France after he showed a class the cartoons depicting Muhammad.

French satirical newspaper Charlie Hebdo first published the cartoons, some of which originally appeared in a Danish newspaper, in 2006. The title reprinted them last year to mark the opening of a trial over a deadly attack on its Paris office in 2015 by two gunmen who had pledged allegiance to al-Qaeda. Twelve people, including nine journalists from the newspaper, were killed.

For many Muslims, depictions of the prophet are blasphemous, and a call by Paris for “reform” of Islam sparked protests across the Muslim world last year. In Pakistan, demonstrators have demanded the expulsion of France’s ambassador to the country, and the release of Tehrik-e-Labbaik’s leader, who was detained earlier this year.

The French Embassy in Islamabad did not immediately return a request for comment.

Prime Minister Imran Khan’s government banned Tehrik-e-Labbaik, declaring it a militant group, not a political entity. Analysts say the group has exploited deeply emotive issues such as blasphemy against the prophet to win popular support.

Three police officers were killed in a separate clash involving Tehrik-e-Labbaik members last week, Reuters reported. Pakistan’s Interior Ministry has since ordered paramilitary rangers to be deployed under anti-terrorism laws. The Islamist group’s followers remain undeterred, vowing to continue their protest all the way to Islamabad, which is more than 200 miles from Lahore.

Rao Sardar Ali Khan, a senior police official, told reporters Wednesday that the government would not allow the radical group to “sabotage” law and order, noting that the slain officers, too, were “lovers of our Prophet, Muhammad.”

Authorities have since placed shipping containers to block entry and exit routes to districts along the busy highway to Islamabad, Reuters reported.

Hussain reported from Islamabad, Pakistan.

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