CIA director Bill Burns has branded Vladimir Putin cocky and smug over the Ukraine war.
The US spy chief also said the West could not afford to be intimidated by Russia’s “sabre rattling and bullying”.
His comments appear to support calls to use long-range western weapons against targets in Russia.
On stage in London with MI6 boss Sir Richard Moore, Mr Burns said: “Putin’s whole narrative right now is a very cocky, very smug one.
“It is, ‘Time is on my side, it’s only a matter of time before the Ukrainians, and their supporters in the West are ground down’.”
Mr Burns revealed in autumn 2022 there was a “genuine risk” that Putin would drop a nuclear bomb.
He said President Biden sent him to warn Russian counterpart Sergey Naryshkin of the consequences.
The US also lobbied China to rein in Putin.
He said Ukraine’s Kursk incursion had “brought the war home to ordinary Russians”.
A Gaza peace plan will be put to Israel and Hamas in days, Mr Burns also revealed.