One person was killed and seven were wounded on Tuesday in a suicide bombing in the eastern Libyan town of Qubbah, a security official said.
Islamic State militants, exploiting a power vacuum amid conflict between two rival governments, have built up a presence in Derna, a city to the east of Qubbah. But there was no mmediate claim of responsibility.
A car packed with explosives hit a checkpoint in the east of the small town, the security official said.
Qubbah lies near the seat of the internationally recognised government, which has worked out of eastern Libya since losing the capital Tripoli to a rival group in August.
In February, militants loyal to Islamic State claimed responsibility for a car suicide bombing that killed 42 people in Qubbah in apparent retaliation for Egyptian air strikes following the killing of 21 Egyptian Copts by the group.
Four years after rebels overthrew Muammar Gaddafi, the oil-producing North African state is in chaos, with two governments and parliaments allied to armed factions fighting for control, while Islamist groups vie for control.