BAUCHI, Nigeria — Gunmen attacked a camp for a construction company in rural northern Nigeria, killing a guard and kidnapping seven foreign workers from Britain, Greece, Italy and Lebanon, authorities said Sunday, in the biggest kidnapping yet in a region under attack by Islamic extremists.

The attack Saturday night happened in Jama're, a town in a rural portion of Bauchi state. There, the gunmen first attacked a local prison, burning two police trucks, Bauchi state police spokesman Hassan Muhammed told The Associated Press.

The gunmen then targeted a worker's camp for a construction company called Setraco, which is in the area building a road, Muhammed said. The gunmen shot dead a guard at the camp before kidnapping the foreign workers, the spokesman said.

Adamu Aliyu, the chairman of the local government area that encompasses Jama're, identified those kidnapped as one British citizen, one Greek, one Italian and four Lebanese.

The Italian news agency ANSA later said authorities confirmed an Italian had been kidnapped in the attack. It quoted Foreign Minister Giulio Terzi saying the safety of the hostage must be given "absolute priority."

The Foreign Office of both Britain and Greece said Sunday they were looking into the kidnappings.

Nigeria's predominantly Muslim north has been under attack by the radical Islamic sect known as Boko Haram in the last year and a half. The country's weak central government has been unable to stop the group's bloody guerrilla campaign of shootings and bombings. The sect is blamed for killing at least 792 people in 2012 alone, according to an AP count.

Foreigners, long abducted by militant groups and criminal gangs for ransom in Nigeria's oil-rich southern delta, have become increasingly targeted in Nigeria's north as the violence has grown. However, abductions of foreigners in the north have seen hostages regularly killed.

In May, gunmen in Kaduna state shot and killed a Lebanese and a Nigerian construction worker, while kidnapping another Lebanese employee. Later that month, kidnappers shot a German hostage dead during a rescue operation. Gunmen who authorities say have links to Boko Haram also kidnapped an Italian and a British man last year in northern Kebbi State who were later killed during a rescue operation by Nigerian soldiers backed up by British special forces. The sect later denied taking part in that abduction, which left Italian authorities angry that the nation was not consulted before the failed rescue attempt.

Chinese construction workers also have been killed by gunmen around Maiduguri, the northeastern city in Nigeria where Boko Haram first began. In the most recent attack, assailants attacked North Korean doctors working for a hospital in Yobe state, stabbing two to death and beheading a third. No group claimed responsibility for that attack.

Foreign embassies in Nigeria have issued travel warnings regarding northern Nigeria for months. Worries about abductions have increased in recent weeks with the French military intervention in Mali, as its troops and Malian soldiers try to rout out Islamic fighters who took over that nation's north in the months following a military coup. Last week, the U.S. Embassy in Nigeria's capital, Abuja, put out a warning following the killings of polio workers in the northern city of Kano and the killing of the North Korean doctors.

"The security situation in some parts of Nigeria remains fluid and unpredictable," the embassy said.

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