KABUL, Nov. 21 (Xinhua) -- At least 13 people were killed and 30 others wounded after a suicide bombing ripped through a mosque in the western part of Kabul, capital of Afghanistan, on Monday, witnesses said.

"The attacker detonated his suicide bomb vest inside Baqir-ul-Ulum Mosque along Faiz Mohammad Kateb road when Shiite Muslim worshipers were holding a religious procession there," witness Mahmood Ullah told Xinhua.

The explosion which occurred at around midday has resulted in multiple casualties, he said.

"The initial information found that 13 people died and some 30 others were injured, but the number of causalities may go up," a security source told Xinhua, adding that many of the wounded were in critical condition.

Details about the incident will be released later in the day, the source noted.

Afghan security forces sealed off the scene, while ambulances and police vehicles evacuated the victims to the city's hospitals.

The witness said there were about 300 people inside the building when the attack occurred and the blast also severely damaged the mosque.

So far, no one has claimed responsibility for the attack.