The US has imposed sanctions on 19 Russians, accusing them of interference in the 2016 US election and alleged cyber-attacks.

They include 13 individuals charged last month by Justice Department Special Counsel Robert Mueller.

Treasury Secretary Steven Mnuchin accused the Russians of “destructive cyber-attacks, and intrusions targeting critical infrastructure”.

The measures are being described as the most significant steps taken against Moscow since Trump assumed office.

The United States also joined Britain, Germany and France in demanding that Russia give explanation on how a former spy was poisoned in Salisbury.