Speaking after the two leaders’ first summit in Geneva, Biden said he laid down the line on Moscow not taking action against hackers who have extorted hundreds of millions of dollars from western governments, companies, and organisations from the safety of Russian soil.

“I pointed out to him we have significant cyber capability and he knows it,” Biden said in a press conference after their talks.

“He doesn’t know exactly what it is, but it’s significant. If in fact they violate these basic norms, we will respond.”