About 200 vehicles with soldiers from Chad and Niger have been seen crossing the border into Nigeria to fight Islamic extremists there, a resident said Monday.
Adam Boukarna, a resident of Bosso which in Niger across Nigeria's northeast border, said that vehicles have been crossing since Saturday. He said after they all crossed into Nigeria loud detonations could be heard, signaling fighting against Boko Haram members.
Nigeria's neighbors are forming a multinational army to confront Boko Haram.
Niger's government has not publicly confirmed this ground assault. The Chadian military spokesman also declined to comment.
Cameroon's minister of defense Edgard Alain Mebe Ngo'o confirmed there was an offensive by Nigeria and Chad but that Cameroon's military was not present because they've been asked to protect Cameroon's borders from the militants.
Boko Haram members have been hiding themselves and supplies in Cameroon, and there are fears that the group may want to escape there when fighting intensifies in Nigeria, he said.
Residents in potential conflict zones in Cameroon have been asked to leave, he said.
Boko Haram's Islamist uprising has killed about 12,000 people in the nearly 6-year-old uprising in northeastern Nigeria.