Two soldiers from Cameroon have been killed and at least two others wounded in an attack by Boko Haram fighters near the Nigerian border, security sources told AFP on Monday.

Speaking on condition of anonymity, one Cameroonian military officer said two troops were killed, and an officer and a soldier injured in a clash on Saturday with the Islamists.

A security source said the troops had been ambushed while patrolling Krawa-Maffa, a northern village located one kilometre (less than a mile) away from the Nigerian border.

On the other side of the frontier, "the Nigerian army is striking Boko Haram's positions almost every day, while the terrorists are trying their hardest to cross over to our side", the Cameroonian source said.

Nigeria's military has claimed a series of major victories over Boko Haram across the northeast during an operation launched in February with support from Cameroon, Chad and Niger.

But the extremists still hold positions along the Cameroonian border with Nigeria, in the Sambisa Forest and Mandara mountains.

Nigeria's authorities say they are winning the war against Boko Haram, and that they aim to recapture the group's Sambisa stronghold by May 29, when president-elect Muhammadu Buhari is due to take office.

Chadian and Cameroonian forces have also seized Boko Haram positions nearby.