MOSCOW (AP) — Pro-Russia separatist leaders in eastern Ukraine ordered a full military mobilization Saturday while Western leaders made increasingly dire warnings that a Russia invasion of its neighbor appeared imminent.

In new signs of fears that a war could start within days, Germany and Austria told their citizens to leave Ukraine. German air carrier Lufthansa canceled flights to the capital, Kyiv, and to Odessa, a Black Sea port that could be a key target in an invasion.

NATO’s liaison office in Kyiv said it was relocating staff to Brussels and to the western Ukraine city of Lviv. Meanwhile, top Ukrainian military officials came under a shelling attack during a tour of the front of the nearly eight-year separatist conflict in eastern Ukraine.

The officials fled to a bomb shelter before hustling from the area, according to a journalist from The Associated Press who was on the tour.

Violence in eastern Ukraine has spiked in recent days as Ukraine and the two regions held by the rebels each accused the other of escalation. Russia on Saturday said at least two shells fired from a government-held part of eastern Ukraine landed across the border, but Ukrainian Foreign Minister Dmytro Kuleba dismissed claim as “a fake statement.”

The United States and many European countries have alleged for months that Russia, which has moved about 150,000 troops near the Ukrainian border, is trying to create pretexts to invade.

“They are uncoiling and are now poised to strike,” U.S. Secretary of Defense Lloyd Austin said Saturday during a visit to Lithuania.

U.S. Vice President Kamala Harris met Ukrainian President Volodymyr Zelenskyy at the Munich Security Conference on Saturday, opening the meeting by saying the world was at “a decisive moment in history.”

Zelenskyy suggested that the West bore some responsibility by not responding more forcefully when Russia annexed Ukraine’s Crimea Peninsula in 2014.