The United States is set to evacuate its embassy in Kyiv as Western intelligence officials warn that a Russian invasion of Ukraine is increasingly imminent. U.S. officials say the State Department plans to announce early Saturday that all American staff at the Kyiv embassy will be required to leave the country ahead of a feared Russian invasion. The State Department would not comment. The department had earlier ordered families of U.S. embassy staffers in Kyiv to leave. But it had left it to the discretion of nonessential personnel if they wanted to depart. The new move comes as Washington has ratcheted up its warnings about a possible Russian invasion of Ukraine. The officials, who spoke on condition of anonymity because they were not authorized to discuss the matter publicly, said a limited number of U.S. diplomats may be relocated to Ukraine’s far west, near the border with Poland, a NATO ally, so the U.S. could retain a diplomatic presence in the country. The Pentagon announced Friday it is sending another 3,000 combat troops to Poland to join 1,700 who already are assembling there in a demonstration of American commitment to NATO allies worried at the prospect of Russia invading Ukraine. Read: US: Civilian toll in Syria raid may be higher than thought The additional soldiers will depart their post at Fort Bragg, North Carolina, over the next couple days and should be in Poland by early next week, according to a defense official, who provided the information under ground rules set by the Pentagon. They are the remaining elements of an infantry brigade of the 82nd Airborne Division. Their mission will be to train and provide deterrence but not to engage in combat in Ukraine. That announcement came shortly after Jake Sullivan, President Joe Biden’s national security adviser, issued a public warning for all American citizens in Ukraine to leave the country as soon as possible. Sullivan said Russian President Vladimir Putin could give the order to launch an invasion of Ukraine any day now. In addition to the U.S. troops deploying to Poland, about 1,000 U.S. soldiers based in Germany are shifting to Romania in a similar mission of reassurance to a NATO ally. Also, 300 soldiers of an 18th Airborne Corps headquarters unit have arrived in Germany, commanded by Lt. Gen. Michael E. Kurilla. Also read: British envoy in Moscow to try to ease Ukraine crisis The American troops are to train with host-nation forces but not enter Ukraine for any purpose. The U.S. already has about 80,000 troops throughout Europe at permanent stations and on rotational deployments.