ONITSHA, Nigeria (Reuters) - Militants have attacked a boat belonging to Nigeria’s state oil firm NNPC in the Niger Delta, killing at least six people, the army said on Thursday.

“During the deliberate attack two soldiers were killed, one wounded, one soldier missing while four civilian staff attached to the house boat were shot dead,” the army said in a statement.

The attack took place on Wednesday in the Warri area, where militants have staged a series of attacks on oil pipelines in recent weeks.