AVDIIVKA, Ukraine • In the trenches of eastern Ukraine, across the tense contact lines with Russia-backed separatists, a soldier’s calm verges on numbness after a sniper’s bullet recently killed one of the 50 or so men under his command.

It is the sort of thing that has happened from time to time in the eight years Ivan Skuratovskyi’s been deployed up and down the 250-mile front line — a member of the Ukrainian army in a war he never imagined when he enlisted in 2013. He grieves, but death and conflict have become an inescapable part of his life.

“The war has put pressure on me and broken my soul,” said Skuratovskyi, 30. “I’m becoming more cold-hearted, some would say dead-hearted. It’s a protective reaction to extreme situations.”

U.S. officials say that with more than 100,000 Russian troops nearing Ukraine’s eastern and northern borders, the threat of a Russian invasion is more serious than others that have come and gone during the years of fighting between the Russia-backed rebels and Ukrainian forces.

The White House national security adviser warned that an all-out invasion could happen any day, and President Joe Biden said “it would be wise” for Americans other than essential diplomats to leave Ukraine .

But even as the rhetoric out of Washington ramps up, a sense of calm prevails in the Eastern European nation among soldiers and citizens alike, from relatives of those in the trenches on up to President Volodymyr Zelenskyy, who campaigned on a promise of ending the drawn-out conflict and has repeatedly called for diplomacy to carry the day.

“We are defending our country and are on our own territory. Our patience can have an impact on provocations, when we don’t respond to provocations but behave with great dignity,” Zelenskyy said.

Ukrainian serviceman Ivan Skuratovskyi walks last week in a trench at a frontline position outside Avdiivka, Donetsk region, eastern Ukraine.

The Associated press