Pakistani police said on Sunday they had detained at least 15 people suspected of being involved in an attack on a Shiite mosque in the city of Quetta that killed at least 47 people.

Humayun Jogezai, deputy police chief in Baluchistan province, said police had rounded up members of various outlawed radical Sunni Muslim groups in overnight raids in southwestern Quetta, where tensions between Shiites and majority Sunni Muslims remained high.

"The detained people are now the part of our investigations but we are looking into all other aspects, including involvement of foreign hands," he added.

Three men had wheeled a trolley up to the gate of the mosque during Friday prayers before pulling guns from under a cover and opening fire on worshippers, police said.