A powerful bomb blast on Monday ripped through a protest in the Pakistani city of Lahore, killing at least 11 people and wounding dozens, according to officials.
The explosion went off in Lahore's busy Mall Road during a rally attended by hundreds of pharmacists protesting against a new government law outside the provincial assembly building.
Jamaat-ul-Ahrar, a Pakistani Taliban-linked armed group, claimed responsibility for the attack, which also wounded at least 30 people, including media personnel covering the protest.
Witnesses told Al Jazeera that the blast occurred near the Punjab assembly building when a suicide bomber on a motorcycle rammed into a police vehicle. Two senior police officials were reportedly killed in the explosion.
"The explosion was heard for several kilometres. It was a very powerful explosive device," Al Jazeera's Kamal Hyder, reporting from the blast site in Lahore, said. Several ambulances arrived at the scene after the blast, while security forces cordoned off the area on Mall Road, one of Lahore's main arteries.
"The road has been sealed off; right now ambulances are evacuating the wounded, and also the police and security forces have gathered at large numbers around the assembly buidling," Hyder said.
Nawaz Sharif, Pakistan's prime minister, condemned the attack and vowed to step up the fight against armed groups in the country.
"Terrorism isn't a novelty for us. Our story has been one of constant struggle against its grasp and a fight for the soul of Pakistan," he said in a statement.
"We have fought this fight against the terrorists among us, and will continue to fight it until we liberate our people of this cancer and avenge those who have laid down their lives for us."
Lahore, in eastern Pakistan, was the site of an Easter Day bombing that killed more than 70 people in a public park last year.
Jamaat-ul-Ahrar claimed responsibility for that attack, as well as for a bombing at a hospital in Quetta that killed 74 people in August last year.