Jeremy Fleming, the head of the UK's cyber-intelligence agency GCHQ, said that Russia has "massively misjudged the situation" in Ukraine.

Fleming said that "Putin's advisers are afraid to tell him the truth." In addition, as reported in the message, the American side came to similar conclusions.

U.S. officials had also suggested earlier that Putin "felt misled by the Russian military" and this had resulted in "persistent tension between Putin and his military leadership".

Putin is also not being told about the full impact of sanctions on the Russian economy, the White House said.