A bomb ripped through a mosque in northern Kabul during Friday prayers and killed 12 worshippers, Afghan police said.

Spokesman Ferdaws Faramarz said the mosque’s imam, Mofti Naiman, was among the dead. Another 15 people were wounded.

The bomb exploded as prayers had begun. No one claimed responsibility for the bombing, but initial police investigations suggest the Imam may have been the target, Faramarz said.

A worshipper at the mosque, Muhibullah Sahebzada, said he had just stepped into the mosque when the explosion went off. Stunned, he heard the sound of screams, including children, as smoke filled the mosque. Sahebzada said he saw several bodies on the mosque floor and at least one child was among the wounded.

It appeared the explosive device had been hidden inside then pulpit at the front of the mosque.

“I was afraid of a second explosion so I came immediately to my home” he said.

An image circulating on social media showed three bodies lying on the floor of the mosque, which showed minor damage.

The explosion comes on the second day of a three-day ceasefire announced by the warring Taliban and Afghan government. The pause was for the Islamic festival Eid-al-Fitr, which follows the fasting month of Ramadan.

Until now many of the attacks in the capital have been claimed by the local Islamic State affiliate, but both the Taliban and government blame each other.

The most recent attack last week killed over 90 people, many of them pupils leaving a girls’ school when a powerful car bomb exploded. The Taliban denied involvement and condemned the attack.

The relentless violence comes as the U.S. and allied NATO forces continue with their final withdrawal from Afghanistan after nearly 20 years of war.

Just this week the last of the U.S. troops left southern Kandahar Air Base, while some NATO troops still remained. At the war’s peak more than 30,000 U.S. troops were stationed in Kandahar, the Taliban heartland. Kandahar was the second largest U.S. base in Afghanistan after Bagram north of the Afghan capital.