The White House has expressed skepticism over Russian leader Vladimir Putin's pledge to respect the results of Sunday's presidential election in Ukraine, instead calling on the Kremlin to ensure that separatists don't disrupt the polling.

Putin, delivering a speech in St. Petersburg, said Moscow "will treat the choice of the Ukrainian people with respect."

But White House spokesman Jay Carney, speaking aboard Air Force One, said Washington would "have to see whether in fact Russia does recognize and then takes steps to engage with the Ukrainian government and the victor of the presidential election."

Carney added: "We further urge Russia to use its influence to persuade separatists in eastern Ukraine and elsewhere to vacate buildings they've occupied, to lay down their weapons, to cease the activities they've engaged in that have caused violence and instability ... and instead to participate in the democratic process in that country."

The remarks came amid heavy fighting in recent days between Russian-speaking separatists and Ukraine government forces in the country's east. On Thursday, as many as 500 separatists attacked a government convoy in a single clash near the village of Rubizhne that left 20 rebels dead, the Defense Ministry said.

Reuters writes:

"At the State Department, spokeswoman Marie Harf said there was evidence that pro-Russian separatists in Ukraine were trying to disrupt the vote."We've seen, particularly in a couple of places in the east, these separatists trying purposefully to disrupt the elections with violence, taking over of government buildings, taking ballot boxes, taking voter registration lists," she said."She also dismissed comments by a Russian deputy defense minister on Friday that Russia intended to pull back all forces deployed to regions near the Ukraine border 'within a few days.'"Copyright 2016 NPR. To see more, visit