Russia handed the United States concrete proposals for binding security guarantees that it wants from the West during a meeting with US Assistant Secretary of State Karen Donfried in Moscow on Wednesday, the Kremlin said.
The US diplomat flew in for talks at a time of soaring East-West tensions over a build-up of Russian troops near Ukraine. Western countries have warned Russia may be poised to launch a new attack on Ukraine, something Moscow has denied.
Russia wants the United States and NATO to guarantee that the Western military alliance will not expand further eastwards or deploy certain weapons systems in Ukraine and other countries that border Russia.
"American representatives were literally today handed concrete proposals in our Foreign Ministry that are aimed at developing legal security guarantees for Russia," Kremlin aide Yuri Ushakov told reporters.
"We are ready to start negotiations on this crucial issue immediately," Ushakov said after a video call between Russian President Vladimir Putin and Chinese President Xi Jinping in which he said Xi had voiced backing for Russia's position.
Donfried met Deputy Foreign Minister Sergei Ryabkov for talks in the ministry earlier on Wednesday and was expected later to meet Dmitry Koazk, Putin's point person on Ukraine.
The Kremlin says NATO's expansion threatens Russia and runs counter to assurances given to it as the Soviet Union collapsed in 1991. NATO says its activities are defensive in nature and designed to deter new Russia aggression, while Washington has repeatedly said that no country can veto Ukraine's NATO hopes.
Donfried travelled to Moscow after holding talks with top Ukrainian officials to offer support in the face of the Russian troop build-up.
Ukraine, long at odds with neighbouring Russia, has stepped up military cooperation with NATO, and the Group of Seven warned Russia last week it would face massive consequences and severe costs if it attacked Ukraine.
Russia annexed Ukraine's Crimea region in 2014 and has supported pro-Russian separatists who seized a swathe of eastern Ukraine that same year.