A suicide bombing at a Shi'ite mosque during Friday prayers in the northwestern Pakistani city of Peshawar killed at least 56 people and injured nearly 200, police and hospital officials said.

An armed man who arrived near the mosque on a motorcycle opened fire when he was stopped by police, before forcing his way into a crowded hall and detonating his suicide vest, senior police official Haroon Rasheed said.

The attacker first shot at the...