A White House spokesman said Wednesday that US officials have seen "no evidence" that Russian troops have pulled back from the tense border with Ukraine.
Russian President Vladimir Putin had earlier said that the estimated 40,000 Russian troops deployed on the frontier had withdrawn to their usual training grounds.
But, speaking to reporters on Air Force One, White House deputy spokesman Josh Earnest said "to date" there has been "no evidence that such a withdrawal has taken place."
His statements echoed those of NATO, which earlier Wednesday reported "no indication of a change in the position of military forces along the Ukraine border."
Washington would "certainly welcome a meaningful and transparent withdrawal," Earnest said. "That's something that we have sought for quite some time."
He was speaking after the Russian leader met with Swiss President Didier Burkhalter, current chief of the Organization for Security and Cooperation in Europe.
Putin said of the troops he had ordered to Ukraine's border two months ago: "We have pulled them back. Today they are not at the Ukrainian border but in places of regular exercises, at training grounds."
Putin said he also told pro-Russian separatists "to postpone the referendums planned for May 11 in order to create the conditions necessary for dialogue."
And he called the nationwide May 25 presidential elections in Ukraine "a move in the right direction."
State Department spokeswoman Jen Psaki welcomed both comments as "helpful" a day after top diplomats slammed the Russian leader for helping to organize what they said was "a bogus" and "contrived" referendum in eastern Ukrainian cities.
But despite Psaki's more conciliatory note, she added "there is far more that President Putin and the Russians can do to de-escalate the situation and to ensure safe elections."
Moves such as supporting the right of all Ukrainians to vote on May 25 and refraining from "any interference with election preparations" would be welcome along with using "their influence" to rein in armed the pro-Moscow armed militias.