The United States and NATO said on Wednesday that they delivered written replies to security demands that Russia had made, DW reports.
Russia had demanded security guarantees that Ukraine would never join NATO, and that the alliance stops its eastward expansion — which the US and NATO rejected.
US Secretary of State Antony Blinken said the document addressed Moscow's concerns and raised those of Washington's allies but made no concessions.
"Putting things in writing is... a good way to make sure we're as precise as possible, and the Russians understand our positions, our ideas, as clearly as possible. Right now, the document is with them and the ball is in their court," he told reporters.
Blinken said he would speak with his Russian counterpart, Sergey Lavrov, in the coming days.
The letter would not be made public, "because we think that diplomacy has the best chance to succeed," Blinken said.
Blinken reiterated Washington's stance on the Russian demand that Ukraine never becomes a NATO member. "I can't be more clear — NATO's door is open, remains open, and that is our commitment," he said.
Meanwhile, NATO Secretary-General Jens Stoltenberg said the military alliance "firmly believes that tensions and disagreements must be resolved through dialogue and diplomacy."
"We are now reaching out to Russia once again to try to pursue a path of dialogue and find a political solution," Stoltenberg said, after the alliance sent Moscow a written response to its security demands.
"But of course while we are hoping for and working for a good solution, de-escalation, we are also prepared for the worst," he said.
"The head of the American diplomatic mission handed over a written response of the US administration to the draft bilateral treaty on security guarantees," the Russian Foreign Ministry said in a statement following Sullivan's meeting with Deputy Foreign Minister Alexander Grushko.
