A suicide bomber reportedly detonated explosives inside Imam Zaman Mosque in Dasht-e-Barchi area in Kabul's PD13.
Kabul Police spokesman Abdul Basir Mujahid confirmed the explosion but said the type of the blast is not known so far.
Hospital officials said two killed and 10 wounded have been taken to nearby health facilities in the west of Kabul city following the explosion.
Sources and eyewitnesses said the explosion claimed more than 30 lives and wounded over 20 others.
Details to follow.