“We need to bring this to a responsible end. We need to restore deterrence, restore peace, and get ahead of this escalation ladder, rather than responding to it,” said Mike Waltz, Trump’s pick for the influential role of US national security advisor (NSA).

In recent days, Washington has authorized Kyiv to use US-supplied missiles to strike targets in Russian territory and agreed to supply it with landmines, prompting Moscow to respond with the use of an experimental medium-range ballistic missile. Waltz, a noted foreign policy hawk and former US special forces officer, has been critical of Russia but has, like Trump, opposed increasing aid to Ukraine.

Ukraine’s President Volodymyr Zelensky has in the past ruled out ceding any territory to Russia, and told Fox News on Tuesday that Ukraine would lose the war if Washington pulls funding. President Joe Biden’s administration has promised a smooth transition to Trump, who has pledged major shake-ups on both foreign and domestic policy.

On Sunday, Waltz said he had met Biden’s NSA Jake Sullivan and warned adversaries abroad against thinking they could gain an advantage in the months before Trump takes office in January. “For our adversaries out there that think this is a time of opportunity that they can play one administration off the other. They’re wrong… we are hand in glove.”