An explosion outside the Punjab Assembly in Lahore on Monday has killed 13 people and injured more than 80, reports said. At least five among the victims were senior police officers. The blast occurred during a protest outside the Assembly by chemists and pharmacists against a government crackdown on the sale of illegal drugs. Negotiations between protestors and the local police were on when the attack took place.

The Jamat-ul-Ahrar faction of the banned Tehreek-i-Taliban Pakistan announced on social media that they were responsible for the attack. The group also said the attack was part of a new campaign against the country’s government departments, Reuters reported.

Prime Minister Nawaz Sharif condemned the attack and said Pakistan would continue to fight terrorism on its soil.

The National Counterterrorism Authority had warned of a possible terrorist attack in Lahore. The Provincial Police Officer and Director General of Pak Rangers Punjab, had issued a notification to the state’s Home Secretary on February 7 and recommended “extreme vigilance and heightened security measures” to “avoid any untoward incident”, Dawn reported.