Nigerian Islamist group Ansaru said on Sunday it was behind the kidnap of a French national last week, citing France's ban on full-face veils and its support for military action in Mali.
Ansaru sent a message to Nigerian reporters saying it was holding 63-year-old Francis Colump, who was taken on December 19 when around 30 gunmen attacked his residence in the remote northern town of Rimi, close to the Niger border.
The Nigerian police declined to comment on the claim but had already named Colump as the man abducted. He was working for French renewable energy firm Vergnet, which had been building Nigeria's first wind farm.
"The reason we kidnapped him is ... the law the government created which prohibits the wearing of niqab by French Muslim women. This is a denial of their religious rights," said the statement by the group, written in the local Hausa language.
"And again the participation of France in supporting the military attack on Muslims in northern Mali," the message signed by the group's purported leader Abu Usamata Ansari said.
In recent months France has led support for an African-led force to help defeat al Qaeda and other Islamist militants in northern Mali. Military deployment has the backing of the U.N. Security Council.
Last year, France banned full face veils.
Ansaru's full name is Jama'atu Ansarul Musilimina Fi Biladis Sudan, which roughly translates as "Vanguards for the Protection of Muslims in Black Africa".
The group, thought to be a breakaway from better known Islamist sect Boko Haram, has risen to greater prominence in recent weeks.
It claimed responsibility for a dawn raid on a major police station in the Nigerian capital last month, where it said hundreds of prisoners were released.
Britain last month put Ansaru on its official "terrorist group" list, saying it was aligned with al Qaeda and was behind the kidnap of a British and a Italian killed earlier this year during a failed rescue attempt.
Ansaru is thought to have loose ties to Boko Haram, which has killed hundreds this year in an insurgency focused mostly on Nigerian security forces, religious targets and politicians, rather than foreigners.
Western governments are increasingly concerned about Islamists in Nigeria linking up with groups outside the region, including al Qaeda's north African wing.
Colump's kidnap takes to nine the number of French citizens currently held hostage in Africa: seven others are in the arid Sahel belt and one in Somalia.
France's Intelligence agency said last week it believed "terrorist" links were behind the latest abduction.
"We are informing the government of France that we would continue to attack ... its citizens anywhere in the world as long as the government does not retract on its policies," Ansaru's statement said. ($1 = 0.7590 euros)
(Additional reporting and writing by Joe Brock; editing by Jason Webb)