Gunmen Sunday kidnapped seven foreigners and killed a security guard when they stormed the compound of a Lebanese construction company, Setraco Nigeria Limited, in Bauchi State.
Those abducted were a Briton, an Italian, a Greek and four Lebanese workers, including two women, police and local government officials said.
No one took responsibility for the kidnap but many are suspecting Islamist group, Ansaru, which rose to prominence only in recent months.
The group had earlier claimed responsibility for the kidnap in December of a French national who is still missing.
Bauchi State Police Commissioner, Mohammed Ladan, said the gunmen attacked a police station and a prison overnight before storming the construction firm's compound in the town of Jama'are.
"We repelled the attack on the police station and the security men at the prison yard also repelled the attack, but they burnt two vehicles in Jama'are police station," Ladan said.
"They then attacked Setraco construction company, killed a local security guard and succeeded in kidnapping people," he said.
Police said they were intensifying efforts to track down the kidnappers in the areas around Jama'are, a remote town around 300 miles north-east of the federal capital Abuja.
Setraco did not respond to requests for comment.
The Italian and Greek foreign ministries confirmed that their nationals were taken in the raid. Britain said it was investigating.
Islamist group, 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'.
It claimed responsibility for a dawn raid on a major police station in the Nigerian federal capital last year, where it said hundreds of prisoners were released.
Last month, it attacked a convoy of Nigerian troops en route to deployment in Mali.
The group said the abduction of the Frenchman last year was motivated by France's ban of the full-face veil and its support for military action against Islamist insurgents in Mali.