Washington, April 1 : Gen. Mark Milley, Chairman of the US Joint Chiefs of Staff, spoke with his Ukrainian and Russian counterparts amid escalating tensions in Kiev. On Wednesday, Milley and Ukrainian Chief of the General Staff Lt. Gen. Ruslan Khomchak discussed the current security environment in Eastern Europe, Xinhua news agency quoted a statement provided by Joint Staff Spokesperson Col. Dave Butler, as saying. "Ukraine is a key partner to NATO and plays a critical role in maintaining peace and stability in Europe," said the statement. Later in the day, Milley also spoke with his Russian Chief of the General Staff Gen. Valery Gerasimov. "The two military leaders exchanged their views on issues of mutual concern," a separate statement said. The phone conversations came amid reports of escalating tensions in eastern Ukraine, which Moscow and Kiev blamed each other for provocative actions. On March 26, Kiev reported that four Ukrainian servicemen were killed during a shelling of the town of Shumy in eastern Ukraine. At the same time, the people's militia of the Donetsk People Republic (DPR) rejected those reports. On Wednesday evening, Pentagon Press Secretary John Kirby told reporters 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. 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 build-up of Russian forces on the border. /IANS