Nigeria's military has linked the beheading of an army couple to the Indigenous People of Biafra (Ipob), a group that wants a breakaway state in south-east Nigeria.
The couple was killed over the weekend while heading to Imo state for their traditional wedding.
Army spokesman Onyema Nwachukwu termed the killings “gruesome, barbaric and most despicable”.
He blamed the armed wing of Ipob - the Eastern Security Network - for the killings.
"The Nigerian army will ensure the perpetrators of this dastardly act unleashed on its personnel do not go unpunished," he said in a statement.
The local Punch newspaper said the attackers made a video of the incident and circulated it online.
Chinasa Nworu, Ipob’s second in command, said the beheadings had nothing to do with the separatists. On Facebook he posted a “fake news” image, saying the story was going to be used by the army as an excuse to step up its operations against Ipob in Imo state.
Ipob was founded by Nnamdi Kanu in 2014.
It wants a group of states in south-east Nigeria, mainly populated by people from the Igbo ethnic group, to break away and form an independent nation called Biafra.