A guard at the site was fatally shot during the raid, which came after an attack on a local police station where two vehicles were blown up.
The group, called Ansaru, which is described as a jihad organization, said Monday it was responsible for the Saturday attack, during which workers from the United Kingdom, Greece, Italy, Lebanon and the Philippines were taken hostage, Britain's Guardian newspaper reported.
The British Foreign Office in London said it was aware of the kidnapping and working with the authorities in Abuja.
When asked whether the United Kingdom would assist in a rescue operation, a No. 10 Downing St. spokeswoman said, "I think that the Foreign Office will want to do what they can."
Ansaru also claimed responsibility for the kidnapping of a French national in December, saying France's ban on full-face veils and its support for military action in Mali were reasons for the abduction. During that attack, 30 extremists raided a house in the northern state of Kaduna, killing two people and kidnapping a French engineer working on a renewable energy project.
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