U.S. Secretary of State Antony Blinken and EU Foreign Secretary David Lammy suggested Putin had already escalated the war by seeking missiles from Iran

Concern about escalation has been one of the reasons why permission has not been given to Kyiv to use western long-range weapons to strike targets inside Russia.

But Blinken said: “Just speaking for the United States, from day one …. we have adjusted and adapted As needs have changed as the battlefield has changed, and I have no doubt that we’ll continue to do that as this, as this evolves.”

Escalation was “one of the factors that we always consider but it’s certainly not the only factor and it’s not necessarily a dispositive factor”.

He added: “We’ve seen Russia now pursue and indeed escalate its attacks inside Ukraine, on civilians, on energy infrastructure, as well as on the Ukrainian military that’s defending its country.

“And we’ve now seen this action of Russia acquiring ballistic missiles from Iran, which will further empower their aggression in Ukraine. So if anyone is taking escalatory action, it would appear to be Mr Putin and Russia”

Lammy said: “It is Putin who has escalated this week with the shipment of ballistic missiles from Iran and we’re seeing this new axis, Russia, Iran, North Korea. We urge China not to throw their lot in with this group of renegades.”