QUETTA, Pakistan — Gunmen riding on a motorcycle shot and killed a local union leader outside a mosque in southwestern Pakistan before fleeing the scene, police and a spokesman for the merchants union said Tuesday.

The assailants gunned down Allahdad Tareen as he came out of the mosque after evening prayers on Monday in the village of Pashin in Baluchistan province, according to police official Zareef Khan. He said an investigation is underway.

The merchants union denounced the killing and said shops and markets would remain closed Tuesday in protest in Quetta, the capital of Baluchistan.

No one immediately claimed responsibility for the attack. Tareen who was known for his struggle to protect the rights of traders and shop owners in Baluchistan.

The province has been the scene of a long-running insurgency by separatists who have staged attacks to press their demands for independence. Militants also have a strong presence in Baluchistan, which borders Afghanistan.