The United States and Nato have sent Russia proposals for disarmament and trust-building measures which could de-escalate the Ukraine conflict, according to documents seen by Spanish daily newspaper El País.

While Nato continues to reject Russia’s key demand of ruling out further expansion to the east, it has offered Russia negotiations on disarmament agreements, including the Organisation for Security and Cooperation in Europe (OSCE) and the US-Russia Strategic Stability Dialogue, the documents show. Meanwhile, the US offered Russia an agreement whereby both sides “refrain from deploying offensive ground-launched missile systems and permanent forces with a combat mission in the territory of Ukraine.”

In response to concerns voiced by Russia surrounding the potential for Tomahawk cruise missiles to be housed in anti-missile shield bases in Romania and Bulgaria, Nato offered a “transparency mechanism” whereby both sides can verify the absence of long-range missiles in bases of their choice.

Russia had previously called for a written reply to its demands from the US and Nato. Russia’s own proposal for de-escalation included a draft of a hypothetical deal for Nato to sign.

Whereas the US’ response to Russia expressed a willingness to discuss the principle of the “indivisibility of security” (the notion that no states should be allowed to strengthen their security at the expense of other nations), Nato’s response indicated an unwillingness to compromise on this issue, according to El País.

Although the Kremlin hasn’t sent a written reply, it has reportedly urged the United States and Nato to unify their responses and for the latter to agree to discuss the “indivisibility of security”.

A call between US Secretary of State Anthony Blinken and Russian Foreign Minister Sergei Lavrov on Decmber 1 was reportedly described as “professional and fairly candid” by a senior State Department official. Lavrov reportedly argued that Russia’s demands on the matter had not yet been met.