Nigeria's most prominent militant group said on Thursday one of its affiliate groups have hijacked a vessel in the Niger Delta and kidnapped 15 of its passengers, according to Reuters. "The Movement for the Emancipation of the Niger Delta (MEND) can confirm that an affiliate group hijacked the MV Spirit yesterday in Delta state and have taken 15 foreign crew members hostage," the militant group said in an emailed statement. It was not possible to independently verify the claim. MEND, a loose coalition of militant groups, on Thursday gave oil companies an additional 48 hours to evacuate their staff in the Niger Delta and threatened to attack helicopters and planes after the deadline.