The governor of the northeastern Nigerian state of Borno has said there are conflicting border claims with Chad and Cameroon in the Lake Chad area, and that Nigeria is losing control of some island villages there.
Governor Mala Kachalla, who made a presentation on Wednesday to the presidential committee on national security in the city of Yola, said the Lake Chad region was also plagued by an influx of armed rebels and large-scale trafficking in illicit arms and children.
"There is no clear cut demarcation between Borno and neighbouring countries along the Lake Chad Basin and the Barkin-Kirawa axis," Kachalla said.
This situation compounded rival territorial claims and made immigration control difficult, he added.
There was now an urgent need to establish checkpoints and aerial surveillance in the border areas to deal with security problems in the region, according to Kachalla.
The Sambisa Games Reserve deserved special attention, having been been identified as a hideout for Chadian rebels blamed for widespread banditry in northeastern Nigeria, he said.
Security agencies in Nigeria have blamed remnants of rebel armies involved in insurrections in Chad and Niger, the country's northern neighbours, for
unusually violent robberies and banditry reported in most parts of the northeast.
Disputes between Nigeria and its eastern neighbour, Cameroon, over the Lake Chad area are among the issues the International Court of Justice (ICJ) at The Hague is expected to address in a ruling later this year.
Cameroon filed a complaint with the ICJ in 1994 after a dispute with Nigeria over the ownership of the oil-rich Bakassi Peninsula in the Gulf of Guinea.