Cameroonian troops this month crossed into Nigeria in pursuit of rebels without seeking authorisation from Nigeria, causing a falling-out between the governments behind the scenes, sources familiar with the matter told Reuters.
At least one incursion was confirmed by a Nigerian government official, two Nigerian military officers and two foreign diplomats, all of whom spoke on condition of anonymity.
Nigerian security forces were deployed to the border to stop any further crossings, said a military source.
The Cameroonian and Nigerian governments said in separate statements there were no incursions. Relations between the two countries are good, Cameroon said.
Cameroonian military officials and pro-government media accuse Nigeria of sheltering Anglophone insurgents. For the past year they have been based in the dense equatorial forests that straddle the border between the two countries, fighting for an independent state they call Ambazonia.
At least 7,000 people have fled as refugees from Anglophone Cameroon to Nigeria following a crackdown ordered this year by President Paul Biya to quell the insurgency, which represents the gravest challenge yet to his 35-year rule.
French is the official language for most of Cameroon but two regions speak English and these border Nigeria, which is also Anglophone.
“Cameroonian troops were in Nigeria,” said a foreign diplomat. “Zero warning, zero authorisation.”
The troops crossed into Nigeria at least twice this month, the diplomat and a Nigerian military official told Reuters.
The incidents have caused anger on both sides and could sour diplomatic relations further as Cameroon increases pressure on its Anglophone regions, according to the diplomat and a Nigerian government official.
“Tensions are high and could escalate,” the government official said.
Cameroon government spokesman Issa Tchiroma Bakary denied that troops had crossed the border illegally.
“Relations between the two countries are cohesive when it comes to fighting against terrorism. Cameroon and Nigeria are on the same wavelength.”
Nigeria’s foreign minister, speaking to Reuters after a cabinet meeting in Abuja, also denied the incursions.
“The (Nigerian) government had investigated and discovered that it’s not true,” said Geoffrey Onyeama, Nigeria’s foreign minister.
But the Nigerian government official and a diplomat said Cameroon had threatened to suspend senior Nigerian embassy officials in Yaounde after they lodged complaints. Tchiroma and Onyeama denied this.
Governments in Africa often play down diplomatic disputes and present a show of harmony even during bitter rows.
On Monday, rebels killed four gendarmes, Cameroon’s government said, the latest raid on police and military positions in the country’s southwest region.