Cameroon has strongly denied allegations that its military systematically executes Boko Haram suspects.

Human rights groups in the Central African nation have asked the U.N. to investigate possible war crimes after reports hundreds of suspects were executed near Cameroon's northern border with Nigeria, an area known to be a Boko Haram stronghold.

Cameroon government spokesman and Communication Minister Issa Tchiroma Bakari said reports by rights groups that the country summarily executes Boko Haram suspects are unfounded.

Speaking to reporters Friday, Tchiroma said Boko Haram prisoners are treated humanely and will be tried "according to the laws of the land."

Tchiroma rejected a report published by the regional human rights group REDHAC in January accusing Cameroon's military of gross abuses against Boko Haram suspects.

However, he admitted some of the suspects the rights group said were killed were found dead in a detention cell in December a day after they were arrested.

"In the early morning it was noticed that 25 out of the 56 had died. The requested forensic doctor expert performed autopsies on the corpses and ordered their burial," he said.

Tchiroma said the Cameroon government had opened investigations to determine the cause of their deaths, said a senior military official he refused to name had been arrested.

"I can already state here that at this stage of investigation, no evidence has been established to corroborate that these persons were deliberately killed," he said. "While waiting, the commander of the gendarme [military] in the far northern region [northern Cameroon] at the time of the incident has been sacked and handed over to competent courts for investigations." He did not try to explain how the suspects might have died.

REDHAC said in its report that the Cameroon military intimidated and tortured suspects to obtain information and that 50 prisoners were suffocated.

Cameroon, Chad and Nigerian soldiers early this year launched a three-nation offensive against Boko Haram fighting to create an Islamist caliphate. Non-governmental organizations and civilians complained innocent people were either killed or arrested.