Armed men accused of belonging to a separatist group killed six people, including four police officers, in southeastern Nigeria’s Ebonyi state, police said on Saturday.
The attack occurred early on Friday near a police checkpoint on a road near the city of Abakaliki, said state police spokesman Joshua Ukandu.
A shootout began in which four officers died and two civilians were killed in the crossfire, he added.
The attackers were still on the run.
They are alleged to be members of the Indigenous People of Biafra (IPOB) movement, which advocates a separate state for the Igbo ethnic group.
Attacks in the southeast are often blamed on IPOB, which systematically denies any involvement in the violence.
Separatism is a sensitive topic in Nigeria, where a three-year civil war broke out in 1967 after Igbo army officers declared an independent Biafra state.
More than a million people died.
President Bola Ahmed Tinubu is also grappling with violence by armed groups in the northwest, known locally as “bandits”, and insurgents in the northeast.