A prominent Pakistani religious scholar has survived an assassination attempt that killed two guards and critically injured another cleric in the southern city of Karachi, police said.

The attack came as the cleric and former Shari'a judge of the country's Supreme Court, Mufti Muhammad Taqi Usmani, was heading to a mosque to lead Friday prayers.

The city's police chief, Amir Shaikh, called the attack a conspiracy to sabotage peace in Karachi and the country.

Usmani and his fellow cleric, Maulana Amir Shahab, were traveling in two cars, when at least four gunmen on two motorcycles opened fire and fled, police said.