A court in Finland has sentenced a controversial leader of a Nigerian secessionist movement to six years in prison after convicting him of terrorism-related offences.

Simon Ekpa, a Finnish citizen of Nigerian origin, "attempted to promote the independence of the so-called Biafra region in south-eastern Nigeria by illegal means", according to court documents made available to BBC News Pidgin by his lawyer.

He also equipped armed groups with weapons and explosives through his network of contacts, the Päijät-Häme District Court ruled, in a unanimous verdict handed down by a panel of three judges.

Ekpa, a former councillor in Finland's Lahti city, denied the charges.

Parts of south-eastern Nigeria have been hit by instability for years because of the conflict between a secessionist movement, the Indigenous People of Biafra (IPOB), and the security forces.

It is unclear whether Ekpa, who was also convicted of aggravated tax fraud, will appeal against the ruling.

The court ruled that he had engaged in illegal activities between August 2021 and November 2024, and had also used social media to incite the public to commit crimes in Nigeria.

Ekpa, who had previously said that he led a faction within IPOB, was arrested at his home in Finland in February 2023.

In 2022, a BBC investigation identified him as one of the "media warriors" of IPOB, who were allegedly using social media to call for violence. He did not respond to BBC requests for comment at the time.

Ipob is banned in Nigeria, and its leader, Nnamdi Kanu, is being tried on terrorism charges in the West African state. He denies any wrongdoing.

The group was formed in 2012 as a peaceful movement, but launched an armed wing in south-eastern Nigeria in 2020, saying it was doing so to defend the Igbo ethnic group.

However, its critics say it has unleashed violence that has caused huge suffering.

The Nigerian government had called for Ekpa's extradition, saying he should face justice in the West African state.

In March last year, the Nigerian army said Ekpa and 96 others were wanted for terrorism, violent extremism and secessionist threats.

Ipob wants the south-east, and part of the Niger Delta, to be their independent homeland, which they call Biafra.

The secessionist campaign first gained impetus in the 1960s, when an Igbo army officer, Emeka Odumegwu Ojukwu, declared the birth of Biafra following killings of south-easterners in northern Nigeria.

But that attempt at secession ended after a bloody three-year conflict that led to more than a million deaths from fighting, starvation and a lack of medical care.