U.S. Vice President Michael Pence has declared that Washington is alarmed by the growing violence in the east of Ukraine.

"We're watching and very troubled by the increased hostilities," Pence told ABC.

Earlier, U.S. President Donald Trump said that Washington will make efforts to ensure peace in the Russian-Ukrainian border.

We will work with Ukraine and Russia and all interested parties to help them restore peace along the border, Trump said in a telephone conversation with Ukrainian President Petro Poroshenko, says a message released by the White House.