Police have closed and evacuated part of Manchester Airport in England after finding an unidentified white powder there.

The action came after airport staff found the power in hand luggage a man planned to carry onto a domestic flight to London on Saturday.

Police have cordoned off the check-in area where the powder was discovered and passengers are being checked in at other terminals. The man is being questioned by police.

Police officer Leor Giladi says there is no imminent danger, but authorities are trying to identify the powder.

The event occurred one day after Britain raised its terror threat alert from "substantial" — meaning a strong possibility of a terrorist attack — to "severe," indicating such an attack is considered highly likely.