Chairman of the Joint Chiefs of Staff General Mark Milley speaks during the daily briefing on the COVID-19 pandemic, in the Brady Briefing Room at the White House on April 1, 2020, in Washington, DC. The top Pentagon general called counterparts in Russia and Ukraine on March 31, 2021 amid increased reports of buildups of Russian troops along Ukraine's border and in Crimea, a US official said. (MANDEL NGAN / AFP)

WASHINGTON - General Mark Milley, chairman of the US Joint Chiefs of Staff, spoke with his Ukrainian and Russian counterparts on Wednesday amid escalating tensions in eastern Ukraine.

Milley and Ukrainian Chief of the General Staff Lieutenant General Ruslan Khomchak discussed the current security environment in Eastern Europe, according to a statement provided by Joint Staff Spokesperson Col Dave Butler.

Pentagon Press Secretary John Kirby told reporters later in the day during a press briefing that "we are concerned about the recent escalation of Russian aggression in eastern Ukraine, including violation of the July 2020 ceasefire"

"Ukraine is a key partner to NATO and plays a critical role in maintaining peace and stability in Europe," said the statement.

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Milley also spoke with his Russian Chief of the General Staff General Valery Gerasimov. "The two military leaders exchanged their views on issues of mutual concern," said a separate statement.

The phone conversations came amid reports of escalating tensions in eastern Ukraine, which Moscow and Kiev blamed each other for provocative actions.

Pentagon Press Secretary John Kirby told reporters later in the day during a press briefing that "we are concerned about the recent escalation of Russian aggression in eastern Ukraine, including violation of the July 2020 ceasefire."

He noted the Pentagon was aware of Ukrainian military reports concerning Russian troop's movement on the border.

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The New York Times reported that the US European Command in the past week raised its watch level from possible crisis to potential imminent crisis, the highest level, in response to the buildup of Russian forces on the border.