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 center in the Dasht-e-Barchi neighborhood 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 spokesperson 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 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, Agence France-Presse 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," 26-year-old Sultan Ali Amiri, who was not in the club when the blast occurred, said. "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 United States-backed government as well as by IS.

The IS group, which considers Shiites heretics, has carried out several deadly attacks in the same area in recent years targeting schools, mosques and gyms.

WITH AFP