Islamist group Ansaru on Monday claimed the kidnapping of seven foreigners in a deadly raid on a construction site in restive northern Nigeria at the weekend.

The attack in Bauchi state late Saturday was the one of the worst incidents targeting foreigners in northern Nigeria, a region that has seen waves of violence by extremist Islamist groups, but relatively few kidnappings.

Ansaru is considered a new group with a rising profile after it claimed the abduction of a French national in December and some view it as being directly linked to Boko Haram, the Islamist insurgents blamed for killing hundreds of people in northern Nigeria since 2009.

In an email statement sent to journalists, Ansaru said it has «the custody of seven persons, which include Lebanese and their European counterparts working with Setraco,» the Lebanese-owned company targeted in the attack.

Police in Bauchi said four Lebanese, one Briton, a Greek citizen and an Italian were among those taken hostage by gunmen who stormed the site in the town of Jama'are in Bauchi state.

Residents in Jama'are, about 200 kilometres (125 miles) from the state capital, said Setraco had evacuated all of its staff from the company compound on Sunday.

Ansaru's two-paragraph statement listed French support for the against Islamist rebels in Mali as a justification for the December kidnapping and appeared to warn of further attacks.

The statement was written in English, which the group has previously used to communicate, however some past statements have been written in Hausa, a language used widely across west Africa.

It was not immediately clear how many of the remaining workers were foreign and an official at Setraco's office in Nigeria's capital declined to comment, also refusing to provide contacts for the company spokesman.

There were two separate gun attacks in the town on Saturday before the abductions.

The kidnapping of expatriates have typically occurred in Nigeria's oil-rich south, with the hostages released following a ransom payment.

But such incidents in the north have been isolated and some analyst fear that Ansaru's emergence may be a sign of changing tactics among the Islamist group's operating in northern Nigeria.

The group is thought to have some ties with Al-Qaeda in the Islamic Maghreb, which has secured huge profits from the abduction of foreigners in several North African countries.

Little is known about Ansaru, with some speculating that the group is a breakaway faction of Boko Haram, although it is possible the two sects operate in concert.

In November, the British government declared Ansaru a terrorist organisation.

The governments of Greece and Italy have confirmed that their citizens were among those taken hostage. Beirut has acknowledged that two Lebanese nationals were seized, but has not matched the police figure of four.

British Foreign Secretary William Hague said Monday that London was in touch with Nigerian authorities following the reports that a Briton was among the seven, but that he had no further information.

Nigeria is Africa's most populous country and top oil producer, roughly divided between a mainly Muslim north and mostly Christian south.

[AFP]