Protesters demanding greater environmental protections for one of the world's biggest saltwater lakes have clashed with security forces in western Iran.

Photographs and video obtained by The Associated Press show police on motorcycles bearing down on dozens of demonstrators in Oroumieh on Aug. 27. The demonstrators threw rocks at police, who fired back. It was unclear whether police used live bullets.

It took several days to confirm the event because residents were fearful of discussing it.

Oroumieh is on the shores of a lake of the same name about 370 miles (600 kilometers) northwest of the capital Tehran. Environmentalists and activists have been raising alarms for years that the lake is threatened by drought and aggressive agriculture policies.