WASHINGTON (AFP) - US Vice President Mike Pence will meet Petro Poroshenko in Washington on Tuesday (June 20), the White House said, but there was no word on whether the Ukrainian president will be hosted by his opposite number Donald Trump.

White House spokesman Sean Spicer said that Poroshenko would meet the US number two, but would not say whether a meeting with Trump is on the cards. Ukrainian officials also refused to comment.

"If we have any updates on the president's schedule we'll let you know later today," Spicer said.

A Poroshenko visit to Washington without meeting Trump is likely to be seen by Kiev as a diplomatic snub, and be cheered by Moscow.

Ukrainian officials have long been concerned about Trump's seeming unwillingness to put pressure on Russian President Vladimir Putin to solve the crisis.

For more than three years Ukraine has been fighting a pro-Kremlin insurgency in its eastern regions that has claimed more than 10,000 lives.

Last week Secretary of State Rex Tillerson suggested that the United States should not be "handcuffed" by an international plan to end the crisis in eastern Ukraine.

The United States, along with European powers, have demanded that both sides withdraw heavy weapons and observe a ceasefire.

Tillerson appeared to argue the United States no longer sees adherence to that accord as a precondition for Russian sanctions relief.