The official, Dr Mohammed Rafique Shehrzad, said 20 bodies were brought to his Main Hospital in Herat city, the capital of western Herat province tonight, soon after the blast shattered the late evening.
Shiites are a minority in Afghanistan and have been threatened by the Islamic State affiliate that operates in the country's east.
No one immediately took responsibility for the attack on the Jawadia Mosque in Herat.
Disclaimer: No Business Standard Journalist was involved in creation of this content