Ukrainian President Petro Poroshenko and U.S. Vice President Michael Pence during a phone conversation have coordinated the schedule of bilateral contacts at the highest level.

The Ukrainian president briefed the U.S. vice president about the aggravation of the security situation in Donbas, in particular the violation of ceasefire regime by Russia, Poroshenko's press service reported.

"Vice President Pence emphasized that the United States fully backs Ukraine in its struggle for restoration of sovereignty and territorial integrity," the report reads.

Poroshenko, for his part, expressed the support of the U.S. actions aimed at preventing the future war crimes of Bashar al-Assad's regime against civilians in Syria.

Pence thanked Ukraine for its solidarity with the U.S. after a chemical attack in Idlib.

Pence also congratulated Poroshenko on the disbursement of another IMF tranche noting the success of the Ukrainian authorities in the implementation of important reforms.