Norwegian police on Wednesday said they had arrested a man on suspicion of incitement to commit crimes against humanity in Cameroon, where a radio station identified him as "separatist leader" Lucas Cho Ayaba.
The Kripos police unit that deals with war crimes and crimes against humanity said in a statement that it had arrested "a man in his 50s" on Tuesday, but did not name him.
"Norwegian police have arrested the separatist leader Lucas Cho Ayaba. He is implicated in atrocities committed in the northwest and southwest," said CRTV radio station.
Two sources had earlier told AFP that Ayaba, 52, was the man arrested.
Cameroon has been gripped since 2016 by a bloody conflict in its two anglophone regions, in the northwest and southwest, between separatists and state forces.
The conflict was sparked by the brutal suppression of peaceful protests in the anglophone regions by long-time President Paul Biya.
"Kripos considers that the suspect is playing a central role in the ongoing armed conflict in Cameroon," the Norwegian police statement said.
The anglophone community, which has long complained of marginalisation and discrimination, makes up about 20 percent of the largely-francophone central African country.
Ayaba is the leader of the Ambazonia Defence Forces, one of the main armed groups operating in the anglophone areas.
International NGOs accuse both the armed separatists and government forces of abuses.
More than 6,000 people have been killed and at least a million displaced during the conflict, the International Crisis Group has said.
A lawyer representing victims of the conflict filed a complaint in the United States against Ayaba and the Norwegian state.
In February, the lawyer, Emmanuel Nsahlai, also petitioned the International Criminal Court to launch an investigation.
Ayaba was a former student union activist in the 1990s and holds German nationality.
It was the first time that Norway had arrested someone on suspicion of inciting crimes against humanity.
If convicted, he could face 30 years in prison.