Unidentified gunmen have killed at least eight people and wounded nine others inside a Shi'ite mosque in Pakistan's southern port city of Karachi.

An interior ministry spokesman said the gunmen opened fire with automatic weapons as people were beginning evening prayers Saturday. Police said about 25 people were inside the mam Bargha Mehdi mosque at the time of the shooting.

The motive for the attack was not immediately clear. Pakistan has been wracked by religious violence in recent years, including attacks by Sunni Muslim extremist groups targeting minority Shi'ites.