U.S. President Donald Trump is set to speak to Russian President Vladimir Putin on Monday about peace in Ukraine as European leaders demanded that the Kremlin accept an immediate ceasefire to halt the region's deadliest conflict since World War Two.

Russia battered Ukraine overnight with its largest drone attack since the war began, Ukraine’s military said Sunday, ahead of an expected phone call between US President Donald Trump and Russian President Vladimir Putin on ending hostilities.

President Donald Trump is hoping separate phone calls with Russian leader Vladimir Putin and Ukrainian President Volodymyr Zelenskyy will make progress toward a ceasefire in the war in Ukraine.