According to the BBC, the controversial leader of a Nigerian secessionist movement was apprehended at his home in Finland.
Simon Ekpa is accused of inciting violence on social media and calling for a boycott of the Nigerian election on Saturday.
He is the leader of a division of the Indigenous People of Biafra (Ipob), a group that is fighting for the creation of a breakaway state in southeast Nigeria.
Finland was requested to take action against him by the government of Nigeria.
Helsingin Sanomat, a prestigious newspaper in Finland, reported that one of its reporters, who went to interview Mr. Ekpa, saw him being led out of his home by police.
From February 23 until after the election, Mr. Ekpa had requested a sit-at-home protest.
A BBC investigation in 2022 revealed Mr. Ekpa to be one of the Ipob "media warriors" who were allegedly inciting violence on social media.
When contacted by the BBC for comment, he remained silent.
His group is "in a revolution and visible state of war," according to Mr. Ekpa.
He also demanded a five-day stay at home period in December of that year, admonishing those who disobeyed to "blame" themselves "for whatever that happens" to them.