US President Joe Biden and Ukrainian President Volodymyr Zelenskyy had their first phone conversation as counterparts on Friday, the White House said in a statement.
"President Biden affirmed the United States’ unwavering support for Ukraine’s sovereignty and territorial integrity in the face of Russia’s ongoing aggression in the Donbas and Crimea", the statement read.
Politico earlier reported that the two discussed the alleged Russian troop movements along Ukraine’s borders.
The reported call comes amid the escalation on the contact line in Donbass, after its armed forced reported four Ukrainian soldiers killed and two more injured in the shelling near the village of Shumy.
The self-proclaimed Donetsk People's Republic (DPR) has repeatedly mentioned the aggravation of the situation over the past two months, reporting increased use by the Ukrainian army of artillery systems and 120-mm and 82-mm mortars.