At least 21 people have been killed in a bomb attack in a busy mosque in Kabul.

According to the police, 33 other mosque visitors were injured in the detonation on Wednesday during evening prayers.

According to police spokesman Chalid Sadran, an explosive device had exploded in the building.

Initially, no group claimed responsibility for the attack.

The blast occurred in a district northwest of the Afghan capital.

Most of the patients sustained injuries from shrapnel and burns.

Taliban spokesman Sabihullah Mujahid confirmed the blast killed and injured but gave no figures.

"The killers of civilians" would "soon be punished for their crimes," he said on Twitter.

Last week, senior Taliban cleric Rahimullah Hakkani was killed in a suicide attack in Kabul.

The jihadist militia Islamic State (IS) claimed responsibility for the attack.

Hakkani had repeatedly preached against IS.

Violence in the country has decreased significantly since the Taliban took power a year ago.

However, IS continues to carry out attacks on a regular basis, primarily targeting religious minorities such as Shiites, Sufis and Sikhs.

Experts see the jihadist militia as one of the key challenges for the radical Islamic Taliban.