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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Two other men missing on Scotland's hills this winter have yet to be found.
The decision was made after two Russian athletes failed drugs tests at the PyeongChang Games.
Sunday will be dry and largely sunny, although there will be some patchy cloud, mainly across eastern Scotland and eastern England.