Many worshippers are feared dead after a massive explosion rocked a mosque in Afghanistan’s capital.

Emergency crews rushed to the Kabul site on Thursday morning and discovered multiple casualties. They are yet to confirm how many people have been killed.

Kabul Emergency Hospital said 27 had been taken to its wards so far, including five children.

It appeared the blast occurred during the mosque’s evening prayers.

Sources suggested the imam of the mosque was among the victims.

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One Taliban intelligence official told Reuters that as many as 35 people may have been wounded or killed, and the toll could rise further.

Al Jazeera quoted an unidentified official as giving a death toll of 20.

Witnesses told Reuters the powerful explosion was heard in a northern Kabul neighbourhood, shattering windows in nearby buildings. Ambulances rushed to the spot.

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“A blast happened inside a mosque…. the blast has casualties, but the numbers are not clear yet,” Kabul police spokesman Khalid Zadran told Reuters.

The Taliban intelligence official, speaking on condition of anonymity, said the explosion occurred in a mosque among worshippers in Khair Khana area of Kabul.

Other officials in the Taliban government did not reply to multiple requests to confirm the number of casualties.

-with AAP