U.S. officials have received a written response from Russia's government to the American proposal on de-escalating Ukraine border tensions, the State Department said on Monday.
Why it matters: The letter comes ahead of a Tuesday phone call between Secretary of State Antony Blinken and Russia's Foreign Minister Sergei Lavrov, and as an estimated 100,000 troops from Moscow amassed at Ukraine's border raise concerns of an imminent Russian invasion.
