Gunmen killed a guard and abducted the Briton, an Italian, a Greek and four Lebanese workers after storming the housing compound of Lebanese construction firm Setraco in Jama'are in Bauchi state late on Saturday.
It was the worst case of foreigners being kidnapped in the mostly Muslim north of Africa's most populous country since an insurgency by Islamist militants intensified two years ago.
"By Allah's grace (we) have the custody of seven persons, which include Lebanese and their European counterparts working with Setraco," read a statement from Ansaru, a group that has kidnapped other foreigners in Nigeria in the past.
The kidnapping was "based on the transgression and atrocities done to the religion of Allah by the European countries in many places such as Afghanistan and Mali," the statement said.
Attacks by fractured Islamist groups in northern Nigeria have become the biggest threat to stability in Africa's top oil producer.
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".