The blast went off in the Guzargah Mosque in Herat during Friday noon prayers, the highlight of the Muslim religious week when places of worship are particularly crowded.
There was no immediate claim of responsibility. Previous mosque attacks have been claimed by the Daesh (ISIL or ISIS) terrorist group, which has carried out a series of attacks against religious and ethnic minorities in Afghanistan, as well as Taliban targets.
In the year since the Taliban takeover of Afghanistan, the Daesh group attacked several mosques in suicide attacks during Friday prayers, with a focus on targeting Shiite Muslims.
The Taliban official, Abdul Nafi Takor, confirmed Friday's explosion and said there were dead and wounded, but had no further details. Takor is a spokesman of the interior ministry in Afghanistan’s Taliban government.