Cameroon's president has sent his army chief to the north of the country to beef up the battle against Nigerian Islamist group Boko Haram.

Following a series of cross-border incursions and kidnappings, President Paul Biya said Saturday he was also sending more troops and military supplies to the area.

Cameroon's president has dismissed two senior army officers deployed in the country's restive north after at least 15 people died in attacks blamed on Nigeria's Islamist Boko Haram movement, state radio reported Wednesday.

At least 15 people were killed in two attacks blamed on Boko Haram in northern Cameroon, with the wife of the country's deputy prime minister among a dozen people reportedly kidnapped, a security source said Monday.

The death toll from the two reportedly simultaneous raids on Sunday by Nigerian Islamic extremists on the palace of the Sultan Kolofata, and the nearby home of one of the country's most senior politicians, deputy premier Amadou Ali, rose on Monday from six to at least 15.

A military court in Cameroon has handed down prison sentences of up to 20 years to 14 Boko Haram members, the country's state broadcaster Crtv reported Friday.

The defendants, who were arrested in March after the discovery of a weapons cache, admitted to being part of the Nigerian extremist group at a "public hearing" in the northern town of Maroua, said the report.

A suspected crossborder raid overnight by Nigeria's radical Islamic group Boko Haram killed two Cameroonian soldiers, a Cameroonian security official said Friday on condition of anonymity.

The attack occurred late Thursday in the border village of Balgaram in northern Cameroon. Eight soldiers posted there fought back, and "in the clash we lost two men," the official said.

In the villages that line the border with Nigeria, even those charged with protecting Cameroonians from Boko Haram fighters fear the fall of darkness. 

Fighting between African migrants in Morocco near the Spanish enclave of Melilla left at least 20 people injured on Sunday, local authorities said.

The unrest broke out in Gourougou forest overlooking the enclave where migrants gather waiting for a chance to sneak into Melilla as a passage to Europe.

Mexico beat Cameroon 1-0 at a rain-drenched Natal on Friday in a World Cup Group A match scarred by more refereeing blunders.

Oribe Peralta grabbed the only goal after 61 minutes but Mexico will consider themselves unlucky not to have been more comfortable winners after Giovani Dos Santos had two goals ruled out for dubious offside decisions in the first half.

Two Italian priests and a Canadian nun seized by suspected Boko Haram gunmen in Cameroon two months ago have been freed, a security source told Agence France Presse Sunday.

The hostages were "freed overnight, at about 2 in the morning. Our soldiers picked them up from a village close to Amchide," in the north of the country, the Cameroonian security source said.

Cameroon on Tuesday began deploying large troop reinforcements to buttress its border with Nigeria against the threat posed by marauding Boko Haram militants, security officials said.

"The deployment has begun. Today, soldiers have started being sent to the border regions," a senior police official in the area told Agence France Presse on condition of anonymity.