Cameroon has accused Nigeria of carrying out a series of attacks in the disputed oil-rich peninsula of Bakassi.

Cameroon's Communication Minister Pierre Moukoko Mbonjo said in a written statement Thursday that Nigerian troops have launched assaults there four times in the past two weeks, leaving one Cameroon soldier dead. He said Cameroon will refer the issue to the United Nations.

Nigeria's Defense Ministry denied the allegations. However, Nigeria's president Olusegun Obasanjo said Thursday he and his Cameroonian counterpart Paul Biya have agreed to launch investigations into the matter.

Nigeria and Cameroon have a long-standing disagreement over the ownership of the Bakassi peninsula, whose waters are prized for their reserves of fish and crude oil.

Cameroon took the matter to the International Court of Justice in the Hague in 2002, and won sovereignty over the peninsula. However, Nigeria has yet to withdraw its troops.

Some information for this report provided by AP, AFP and Reuters.