By John Irish and Joe Brock
PARIS/ABUJA (Reuters) - A French energy worker has been kidnapped in northern Nigeria after 30 gunmen attacked a residence and killed a policeman and a security guard protecting the foreign employee, officials said on Thursday.
No group claimed credit for the abduction but Islamist groups linked to Boko Haram, which has killed hundreds in an insurgency this year, have been behind similar kidnappings in the past and become the biggest security threat to Africa's largest oil exporter.
Local Nigerian police spokesman Aminu Sadiq Abubakar said the attack took place on Wednesday in the town of Rimi about 20 kilometers (12 miles) north of Katsina, very close to the border with Niger. A police station nearby had also been bombed and some inmates freed from detention, Abubakar said.
The kidnapped worker was employed by French renewable energy firm Vergnet, officials said. A Paris-based Vergnet executive confirmed the kidnapping.
Vergnet is a French firm specializing in wind power turbines, with 700 globally. The company is currently building Nigeria's first wind farm based in Katsina state.
French President Francois Hollande, on a visit to Algeria, confirmed a French man had been kidnapped and two Nigerians killed during the attack.
"We will use all our means to find our national," he said at a press conference in Tlemcen.
French Foreign Minister Laurent Fabius, who was travelling with Hollande in Algeria, told France 2 radio there had been no claims of responsibility for the kidnapping.
Two Frenchmen were killed last year in a failed rescue attempt after being snatched by al Qaeda linked groups from a bar in Niger's capital Niamey.
Seven people were abducted in the northern city of Arlit a year earlier, including five French nationals. Four of those are still being held.
"While we have no firm concrete news, the location and style of the attack suggests Boko Haram or a faction of the group," said Peter Sharwood-Smith, Nigeria country manager of security firm Drum Cussac.
A Briton and an Italian were abducted in May last year in Nigeria's northwestern region and their captors killed them during a British-Nigerian rescue mission in March this year.
Britain last month officially labeled a Nigeria-based Islamist group called "Ansaru" as a "terrorist organization". It said it was aligned with al Qaeda and was probably responsible for the killing of the two men.
Boko Haram has in the past sent some of its members to train with Al Qaeda's north African wing in Niger, security experts and foreign diplomats say.
Ansaru has loose ties with Boko Haram, security experts say.
Boko Haram has killed hundreds in its insurgency this year, focusing its attacks on security and religious targets in an effort to carve out an Islamic state in a country of 160 million split roughly equally between Christians and Muslims.
Seven French nationals are already in the hands of kidnappers in the Sahara, and one is held in Somalia.
At the opposite end of Nigeria, in the oil-producing Niger Delta there have been several kidnappings both onshore and offshore in recent weeks.
However, abductions in the oil-region tend to be carried out by criminal gangs for ransom, rather than by extremists. It is a multi-million dollar business and victims are usually released.
(Additional reporting by Augustine Madu in Kano, Isaac Abrak in Kaduna and Alexandria Sage in Paris; Editing by Daniel Flynn, Mark John and Sophie Hares)