KABUL , (Xinhua) -- At least 21 people were killed and 33 others injured late Wednesday in an explosion targeting worshipers at a mosque in the Afghan capital, Kabul, a security official confirmed Thursday.

In a press conference, Khaled Zadran, a spokesman for the Kabul police, confirmed that: "The explosion occurred during evening prayers inside a mosque in Police District No. 17, killing 21 people and injuring 33 others on the spot."

Eyewitnesses heard a loud explosion that shattered the windows of nearby buildings.

No one has claimed responsibility for the fatal accident so far.

The blast came just days after a prominent pro-Taliban cleric was killed in a suicide bombing in the capital, Kabul, claimed by the Islamic State group.