On 5 January, Nigerian officials arrested Sisiku Ayuk Tabe, the leader of the Anglophone separatist movement, the Governing Council of Ambazonia, along with 46 other people. Nigeria returned the 47 to Cameroon, which called the men "terrorists" and said they would "answer for their crimes", on Monday.

The UNHCR said most of the group had submitted asylum claims in Nigeria, and so their return violates the principle of non-refoulement, which says migrants cannot be sent back to a country where they might face persecution.

"The UNHCR reminds Nigeria of its obligations under international and Nigerian law, and urges the Nigerian Government to refrain from forcible returns of Cameroonian asylum-seekers back to their country of origin," the agency said.

Mr Tabe wants the anglophone Southwest and Northwest regions of Cameroon to separate from the Francophone ones, claiming that these areas are subject to economic inequality and social injustice.

On 1 October, the Governing Council of Ambazonia symbolically declared independence.