Kiev - Ukraine said on Tuesday that Russian troops had moved away from the border, just five days before the country's make-or-break presidential poll, but stopped short of confirming a full withdrawal as demanded by the West.
Moscow had announced it was pulling back its forces in a move that has the potential to deflate a bloody Kremlin-backed insurgency threatening to tear the ex-Soviet nation apart.
Kiev's Western-backed leaders were also boosted on Tuesday when Ukraine's richest man Rinat Akhmetov denounced the armed rebels who have overrun a dozen cities in his eastern industrial power base as bandits who might create "genocide".
Ukraine's border service issued a surprise announcement early on Tuesday that none of the estimated 40 000 Russian soldiers were now stationed within 10km of the country.
But Foreign Minister Andriy Deshchytsia, on a visit to Berlin, later said he could not confirm a withdrawal.
"I hope that the declarations by Russian politicians that the troops are to be withdrawn from Ukraine's borders do not just remain declarations".
Tensions between Moscow and the West have spiralled to Cold-War highs over the crisis in Ukraine, particularly Russia's annexation of Crimea in March and allegations it is driving a bloody insurgency in the east.
The United Nations estimates that around 130 people have died since violence in the Donetsk and Lugansk regions near the Russian border first broke out in early April.
The UN refugee agency said another 10 000 people - many of them ethnic Tatars in Crimea - have been internally displaced.Move could 'de-escalate' crisis
The United States and Nato have sent troops to Poland and the three tiny Baltic nations to calm jitters about Russian troops possibly not only overrunning Ukraine but also pushing further into Europe in a bid to reclaim ex-Soviet satellite states.
Nato chief Anders Fogh Rasmussen had said on Monday that a real Russian withdrawal - following several earlier promises by President Vladimir Putin - would be an "important contribution to de-escalating the crisis".
But the war of words between Washington and Moscow showed no signs of a let-up.
Russian Prime Minister Dmitry Medvedev said in an interview broadcast on Tuesday that Moscow and the West were still "slowly but surely" approaching a second Cold War.
And US Vice President Joe Biden, on a visit to Romania, blasted Russia's seizure of the Crimean peninsula, saying: "Europe's borders should never again be changed at the point of a gun".
Both Kiev and its Western allies see Sunday's presidential vote - backed only grudgingly by Moscow - as a chance to unite the culturally splintered nation and win more legitimacy in the Kremlin's eyes.
However, the Kiev authorities have admitted that they will have a hard time ensuring that polling proceeds smoothly in the two eastern districts where the rebels still control dozens of cities and towns.'Fear and terror'
But in a move that some say could turn the tide against the rebels, key powerbroker Akhmetov condemned the insurgency and called people to stage rallies for peace.
"People are tired of living in fear and terror," said the Donetsk native who once funded the deposed pro-Kremlin regime but is now seeking to build closer relations with the new Kiev team.
The Ukrainian government hailed Akhmetov's intervention, with Interior Minister Arsen Avakov said it "will help [Ukrainians] settle our differences and let our rifles gather dust".
Putin - currently in China - has denied any direct role in the uprising and has so far refused to recognise the independence proclaimed by Donetsk and Lugansk in 11 May referendums that both the West and Kiev have denounced as a sham.
Russia has recently rolled back its vehement opposition to Sunday's election but also called on Kiev to immediately withdraw all its troops from the east.
UN assistant secretary-general for human rights Ivan Simonovic cautioned on Monday against expecting that the election would produce a "miracle" for Ukraine.
Ukraine's military has so far failed to dislodge the rebels and suffered a number of humiliating setbacks since it launched its "anti-terrorist" offensive five weeks ago.
The international community is pushing for a negotiated settlement under a peace roadmap sponsored by the Organisation for Security and Cooperation in Europe.
Two rounds of national unity dialogue have been held but Kiev's leaders have refused to invite the separatists - to the deep annoyance of Moscow.
A simmering row over energy supplies also flared again on Tuesday when Ukrainian Prime Minister Arseniy Yatsenyuk rejected Russia's demand for Kiev to pay up front for all gas deliveries starting in June because of billions of dollars in debts.
Russia's state gas giant Gazprom warned last week it may halt shipments to Ukraine on 3 June in a repeat of previous energy wars that also limited supplies to nearly 20 nations in western and southern Europe.
Nearly 15% of all gas consumed in Europe is delivered from Russia via the ex-Soviet state.