US makes decision on Russia's request to stop Ukraine joining NATO

State Secretary Antony Blinken said Washington had prepared Moscow a “serious diplomatic path” to resolve the confrontation, in a private letter to the Russian government.

We make it clear that there are fundamental principles that we are committed to support and protect, including the sovereignty and territorial integrity of Ukraine, and the right of states to choose their security agreements and alliances”, he said.

Blinken addressed the media shortly after his deputy Wendy Sherman said the United States remained convinced Putin was ready to use force against Ukraine by mid-February.

He said the letter stressed that Kiev could choose its allies, rejecting Moscow's bid for a promise that Ukraine would not join NATO's alliance.

Blinken told reporters that the letter would not be made public, “because we think diplomacy has the best chance of success”.

He said he will speak with Russian Foreign Minister Sergei Lavrov in the coming days of his response to the US stance.

“We have addressed the possibility of mutual transparency measures regarding the force and Ukraine's account, as well as measures to boost confidence about military exercises and maneuvers in Europe”, he said.

The letter, which was co-ordinated with Kiev and US allies in Europe, also opens the door for advancing arms control talks with Russia on the issue of rockets and nuclear weapons deployed in Europe.