The Islamic State jihadist group claimed on its Telegram channel Friday that it was behind a blast at a sports club that killed four people in the Afghan capital the night before.
The Sunni Muslim extremist group said it had used a parcel bomb that "IS fighters placed in a room where Shiites gather".
The explosion occurred Thursday evening at a commercial centre in the Dasht-e-Barchi neighbourhood of Kabul, an enclave of the historically oppressed Shiite Hazara community, according to police.
Police were still investigating the cause of the explosion, Kabul police spokesman Khalid Zadran said on Friday afternoon in a message to reporters.
He added that seven people were injured in the blast, revising the initial toll of two dead and nine injured.
Taliban authorities did not immediately respond to a request for comment on the Islamic State (IS) claim.
The explosion ripped through a sports club several floors up in the commercial centre, blowing out all the sides of the space and shattering windows and causing damage throughout the block, AFP journalists saw on Friday.
An instructor at the club, which holds training in combat sports, told AFP the blast happened at the end of a busy boxing session that usually hosted some thirty people.
"The explosion was extraordinarily strong. The walls fell, the metal doors, glass and windows were broken", said 26-year-old Sultan Ali Amiri, who was not in the club when the blast occurred. "There has been a lot of damage, punching bags and almost everything is destroyed".
AFP journalists saw several heavy bags used for combat sport training on the floor of the club, others still hanging and pocked with fragments from the blast.
Afghanistan's Hazaras have regularly faced attacks in the majority Sunni Muslim country.
They have been persecuted for decades, targeted by the Taliban during their insurgency against the former US-backed government as well as by IS.
The Islamic State group, which considers Shiites heretics, has carried out several deadly attacks in the same area in recent years targeting schools, mosques and gyms.
Images shared on social media shortly after the explosion showed a fire blazing in the sports club and boxing mitts among shattered glass on the ground.
The number of bomb blasts and suicide attacks has reduced dramatically since the Taliban ended their insurgency after seizing power in August 2021, ousting the US-backed government.
However, a number of armed groups -- including the regional chapter of IS -- remain a threat.