A car bomb blast killed at least four people and wounded 10 others near a mosque in the Libyan city of Benghazi on Tuesday night, security and medical officials said, according to Arabiya News.
The explosives-rigged vehicle blew up in front of a mosque in the central neighborhood of Al-Sleimani, a security source said.
The mosque is known to be a base for Salafist groups which fought jihadists in the eastern port city alongside forces loyal to military strongman Khalifa Haftar.
The death toll was expected to mount, according to a source at Benghazi's Al-Jala hospital.
Libya has been rocked by chaos since a 2011 uprising that toppled and killed dictator Muamar Ghadafi, with two rival authorities and multiple militias vying for control of the oil-rich country.
Military strongman Khalifa Haftar in July announced the "total liberation" of Benghazi, three years after his forces launched a military operation to seize the city from jihadists who had made it a stronghold following the revolution.
But clashes and attacks in the city have continued, including against diplomatic facilities and security forces.
Haftar supports a parliament based in the far east of Libya, while a rival United Nations-backed unity government in the western capital Tripoli has struggled to assert its authority nationwide.