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:
More top news
A comedy drama series which details the lives of Russian expats in London will air tonight.
A 65-year-old man was attacked by a shark in Australia on Friday, leaving him with serious leg injuries.
Nearly one million people could have their homes repossessed because they do not have a plan to pay off their interest-only mortgages.