Washington and its NATO allies have offered Moscow arms control and trust-building measures to defuse the threat of a new Russian offensive against Ukraine, according to documents published by El Pais on Wednesday.

The proposals, set out in letters by NATO and the United States last month in response to Russian demands, remain firm on insisting that Ukraine and any other sovereign country has a right to apply to join the alliance.

But the reported U.S. response, posted to the Spanish daily's website, suggests "reciprocal commitments by both the United States and Russia to refrain from deploying offensive ground-launched missile systems and permanent forces with a combat mission in the territory of Ukraine."

Both the U.S. and NATO documents urge Russia to restore diplomatic ties with the alliance and to renew and renegotiate nuclear missile control treaties with the United States.

Moscow is urged to re-engage with the NATO-Russia council, a diplomatic body "offering dialogue and partnership in place of conflict and distrust."

A NATO official refused to confirm the text, saying: "We never comment on alleged leaks."

Kremlin spokesman Dmitry Peskov said Moscow was aware of the report but added: "We didn't publish anything, and I don't want to comment on this."