The United States said on Wednesday it had set out a diplomatic path to address sweeping Russian demands in eastern Europe, as Moscow held security talks with Western countries and intensified its military build-up near Ukraine with new drills.

In a written response to Russia's demands delivered in person by its ambassador in Moscow, the U.S. repeated its commitment to upholding NATO's "open-door" policy while offering a "principled and pragmatic evaluation" of the Kremlin's concerns, Secretary of State Antony Blinken said.

Russia has demanded NATO pull back troops and weapons from eastern Europe and bar its neighbor Ukraine, a former Soviet state, from ever joining. Washington and its NATO allies reject that position but say they are ready to discuss other topics such as arms control and confidence-building measures.