Francis Colump, 63, an engineer with a France-based company Vergnet, was abducted last week in northern Nigeria's Katsina state, where he was working on a wind power project.
Ansaru, in a statement to journalists, gave as reasons for their attack, France support for military intervention in Mali and flouting of Islamic laws.
It said the law that outlaws the use of Islamic veil by Muslims women in France is an infringement on their religious rights.
"This group will continue launching attacks on the French government and French citizens... As long as it does not change its stance on these two issues," Ansaru said.
The new Islamic sect which has affiliation to Boko Haram, another sect that has killed thousands by suicide bombings, shootings and by using explosives was recently outlawed by the British government.
Britain had fingered the group in the kidnapping of a French and Italian in northern Nigeria last year.
French backed the sending of troops to Mali to flush out the Islamic militants which have taken over the northern part of the country.
Abuja: A new radical Islamist group, Ansaru has claimed responsibility for the kidnapping of a French national in northern Nigeria, citing the stance of France on Islam and its military intervention in Mali as justification.
First Published: Monday, December 24, 2012, 09:20