US holds firm on Ukraine’s right to join Nato in its response to Russian demands

The US has presented its written response to Russian demands on Ukraine, but made clear that it did not change Washington's support for Ukraine's right to pursue Nato membership, the most contentious issue in relations with Moscow.

The reply, which was delivered to the Russian foreign ministry by the US ambassador in Moscow, John Sullivan, repeats the US offer to negotiate with Russia over some aspects of European security, but the secretary of state, Antony Blinken, said the issue of eventual Ukrainian membership of the alliance was one of principle.

Blinken was speaking hours after his Russian counterpart, Sergei Lavrov, threatened "retaliatory measures" if the US response did not satisfy the Kremlin.

"Without going to the specifics of the document, I can tell you that it reiterates what we said publicly for many weeks, and in a sense for many, many years. That we will uphold the principle of Nato's open door," Blinken said, adding: "There is no change. There will be no change."

He said the US document would not be made public because "we think diplomacy has the best chance to succeed if we provide space for confidential talks".

Nato delivered its own response to Moscow on Wednesday with the same message on Ukrainian membership.

"Nato is a defensive alliance and we do not seek confrontation, but we will not compromise on the values on which our alliance rests," the secretary general, Jens Stoltenberg, told reporters, warning that "we face a critical moment in Euro-Atlantic security".