BAUCHI, Nigeria — Gunmen attacked a camp for a construction company in rural northern Nigeria, killing a guard and kidnapping seven foreign workers from Britain, Greece, Italy, Lebanon, and the Philippines, authorities said Sunday, in the biggest kidnapping yet in a region under attack by Islamist extremists.

The attack Saturday night occurred in Jama’are, a town in Bauchi state. There, the gunmen first attacked a local prison, burning two police trucks, Bauchi state police spokesman Hassan Muhammed said.