The Home Office is not confirming or denying whether any British workers have been involved.
But officials say they are investigating reports which suggest at least one Briton was taken when gunmen stormed a compound belonging to a Lebanese construction company in Nigeria.
ITV News reporter Sejal Karia talks from outside the Foreign Office:
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Tonight will start off clear in many areas, but cloud will increase from the east overnight, bringing some light and patchy rain.
Defending champions Arsenal squeezed into the FA Cup final despite a spirited fightback from Reading, who forced extra-time
A detective who led investigations into the Valley Parade fire tells ITV News there is "unequivocal" evidence the disaster was an accident.