The leader of a Cameroonian separatist movement was taken from a hotel in Nigeria by a group of armed men, an eyewitness has told the BBC.
Officially Nigeria’s domestic intelligence agency, the DSS, has denied arresting Sisiku Julius Ayuk Tabe and nine of his colleagues.
But a source within the agency told the BBC that it was involved in the operation, alongside operatives from Cameroon.
Mr Ayuk Tabe’s separatist group, the Governing Council of Ambazonia (GCA), has released a statement demanding his release.
According to the eyewitness, at least 15 people in military clothing came to the hotel in Abuja at 7pm on Friday evening and apprehended the group who were holding a meeting there.
The eyewitness said it wasn’t clear where those co-ordinating the arrest were from, though some were Nigerians.
The GCA was a fringe political group until recently when Anglophone protests against Cameroon’s predominantly French-speaking government were violently suppressed. Mr Ayuk Tabe had been based in Nigeria.
It is seen as one of the biggest political challenges to the 35-year rule of Cameroon’s President Paul Biya, and it comes as Nigeria is also dealing with its own Biafran separatists in the south-east of the country.