At least 19 people were killed and 30 injured Friday when militants stormed a Shiite Muslim mosque in Peshawar in northern Pakistan.
Witnesses said the gunmen wore the uniforms of paramilitary forces and exchanged fire with guards manning the main entrance of the mosque in Hayatabad Township.
The Pakistani Taliban claimed responsibility, releasing pictures of three suicide bombers who the militant organization said took part in the attack. Police said that a total of four attackers were involved.
The group said the attack was in retaliation for the execution of a militant named Dr. Usman, who was hanged Dec. 20 for his alleged involvement in an attack on Pakistani army headquarters in Rawalpindi in 2009. Pakistani authorities have resumed executions of terrorism suspects since December, when the Pakistani Taliban attacked an army-run school in Peshawar, killing 132 children and 16 adults.
"The government should wait for more attacks," a statement from the Pakistani Taliban said.
The attack occurred during weekly Friday services, when police said about 200 people were offering prayers at Imamia Mosque.
"I was standing in the third row inside the main hall of the mosque and offering prayers when heavy gunfire started," said Yaqoob Ali, who received shrapnel injuries on the right leg.
"I saw three attackers who were wearing the uniform of the paramilitary forces and started firing indiscriminately on worshipers," he said, adding that the attackers were young.
Police said the attackers scaled the mosque's main outer wall from the backside and wore vests laden with explosives. Khyber Pakhtunkhwa province police chief Nasir Khan Durrani told reporters that four militants with explosive vests attacked the mosque. He said three of them blew themselves up but that the fourth's jacket could not explode.
Witnesses and officials said the gunmen set their vehicle on fire before launching the attack, and that the attackers lobbed grenades. Three explosions were heard inside the compound. Police said they defused the grenades and an explosive vest lying inside the mosque.
After the attack, Health Minister Shahram Tarakai said, 19 bodies and 30 wounded people were taken to Hayatabad Medical Complex, the government-run hospital in the township.
It was the second major attack in weeks targeting Pakistani Shiites, who make up between 15% and 20% of the population. A bombing Jan. 30 at a Shiite mosque in the southern province of Sindh killed at least 49 worshipers.
The attacks come after a drop in sectarian violence in Pakistan in 2014, when 210 Pakistanis were killed in communal attacks, less than half the toll of the year before, according to the South Asia Terrorism Portal.
Ali is a special correspondent. Times staff writer Shashank Bengali in Jaffna, Sri Lanka, contributed to this report.