Truss said she would not detail now who Britain planned to target with the new measures.

"We will make sure that those who share responsibility for the Kremlin's aggressive and destabilising action will share in bearing a heavy cost," Truss told parliament.

"Their assets in the UK will be frozen. No UK business or individual would be able to transact with them. And should they seek to enter the UK, they would be turned back."

(Reporting William James, Writing by Kylie MacLellan. Editing by Andrew MacAskill)