By Tansa Musa
YAOUNDE, Aug 26 (Reuters) - Around 480 Nigerian soldiers crossed into Cameroon after Boko Haram militants operating along the border between the two nations attacked a military base and police station, authorities in Cameroon said on Tuesday.
The apparent retreat across the border may suggest Boko Haram is having some success at chasing Nigerian forces out of towns they are defending along the hilly frontier with Cameroon.
The soldiers crossed to the Cameroon town of Fotokol in the Far-North region after fighting broke out when the Islamist militants attacked a base and police station in Gamboru in neighbouring northeastern Nigeria, Cameroon Ministry of Defence spokesman Lieutenant-Colonel Didier Badjeck said.
The Nigerian military said some troops had crossed the border in a "technical manoeuvre" after sustained fighting with Boko Haram in the town, but it did not say how many.
Boko Haram leader Abubakar Shekau said in a videotape released on Sunday that his fighters now ruled the captured northeastern town of Gwoza, also next to Cameroon, "by Islamic law", a sign the militants may now be fighting to secure territory instead of just to destabilise the northeast.
"The unarmed Nigerian soldiers have been accommodated in a school in Maroua and negotiations are currently going on so that they can return to their country," Badjeck told Reuters.
Boko Haram has killed hundreds of people this year, mostly in northeastern Nigeria, and it has staged bombings across the country. The group, which rejects Western-style education and seeks to carve out a de facto Islamic state in northern Nigeria, shocked the international community in April when it abducted 200 Nigerian schoolgirls.
In recent weeks it has stepped up cross-border attacks into Cameroon, leading Cameroon to increase its deployment of troops to its northern region, joining international efforts to combat the militants.
Nigeria's Defence Ministry spokesman Major-General Chris Olukolade said the troops charged across the border in a tactical manoeuvre during a sustained battle with the militants.
"Being allies, the normal protocol of managing such incidents demand that the troops submit their weapons in order to assure the friendly country that they were not on a hostile mission," he said by email.
The troops were on the way back to rejoin their unit, he said, adding that Nigeria's defence forces had also repelled an attack by Boko Haram at Gamboru.
Cameroonian Colonel Felix Nji Formekong said one of his country's soldiers was wounded in the fighting.
Badjeck said Cameroon's forces beat back the Boko Haram attack, and he appealed for fresh troops to help stabilize the border region.
"The battle went on for a long time until the Boko Haram elements came face-to-face in the afternoon with Cameroonian soldiers deployed to the region. Our troops killed many of them ... and succeeded in repulsing them," Badjeck said.
Cameroon closed its borders with Nigeria on Aug. 19 in a bid to halt the spread of the Ebola virus, which has killed at least five people in Nigeria. Neither country mentioned that move in their comments about this week's incident. (Additional reporting by Lanre Ola in Maiduguri, Nigeria; Writing by Matthew Mpoke Bigg; Editing by Hugh Lawson)