Russia raised the stakes in the Ukraine crisis on Monday by saying it respected what rebels claimed was a resounding vote in favor of self-rule in the east of the country.

But the Kremlin also called for dialogue between authorities in Kiev and rebel leaders, as European Union ministers prepared to meet in Brussels to consider toughening sanctions on Russia.

Russia's deputy prime minister said Sunday he had managed to bring to Moscow boxes of petitions asking Russia to recognize Moldova's breakaway Transdniestr region despite an attempt by authorities in Chisinau to confiscate them.

Transdniestr, which borders Ukraine and is mainly Russian-speaking, declared independence from Moldova in 1990 and has Russian troops stationed there but is not recognized by any country.

President Vladimir Putin reviewed Russian ships in the port of Sevastopol on Friday as he visited Russia's naval base in the Crimean port for the first time since Moscow's annexation of the Black Sea peninsula.

Russian television showed live footage of Putin standing on a white vessel passing at least 10 navy ships in the port, stopping at each to congratulate the sailors for Victory Day, Russia's celebration of the defeat of Nazi Germany.

U.S. President Barack Obama has no plans to meet one-on-one with his Russian counterpart Vladimir Putin in June when both attend the D-Day anniversary in France, the White House said Thursday.

Russia's intervention in the political crisis in Ukraine has triggered the worst chill in relations between Washington and the Moscow since the end of the Cold War.

Russian President Vladimir Putin will attend ceremonies in France next month marking the 70th anniversary of D-Day despite the Ukraine crisis, the ambassador to Paris said Thursday.

"President Putin has been invited by President (Francois) Hollande to take part in the ceremonies to commemorate the Normandy landings on June 6. He has accepted the invitation. He will be coming on June 6," Alexander Orlov told BFM television.

NATO said Thursday it had yet to see "any indications" that Russia has withdrawn its troops from the Ukraine border, a day after President Vladimir Putin claimed to have done so.

"Let me assure you that if we get visible evidence that they are actually pulling back their troops, I will be the very first to welcome it," NATO Secretary General Anders Fogh Rasmussen said in Warsaw.

Russia on Thursday test-launched several ballistic missiles during planned exercises overseen by President Vladimir Putin, news reports said, as a crisis raged in neighboring Ukraine.

The Russian military fired a Topol intercontinental ballistic missile from its northern test site in Plesetsk, as well as "several" shorter-range missiles from its submarines in the Northern and Pacific Fleets, news agencies cited defense officials as saying.

Pro-Moscow rebels fighting in east Ukraine vowed Thursday to press on with disputed independence referendums, defying a call from President Vladimir Putin to postpone the vote in a bid to ease tensions.

"The vote will happen on May 11," the leader of the self-proclaimed People's Republic of Donetsk, Denis Pushilin, declared to reporters.

Russia's President Vladimir Putin on Wednesday told pro-Russian rebels fighting in east Ukraine to halt plans for independence referendums and said his troops had pulled back from the border, in a potential breakthrough in the worst showdown between Moscow and the West since the Cold War.

The Russian leader also hailed a planned May 25 presidential election in Ukraine -- previously criticized by the Kremlin -- as a "move in the right direction".

Russia is gearing up for hugely patriotic celebrations of its victory over Nazi Germany in World War II on Friday, but festivities in neighboring Ukraine will be muted amid fears of provocations.

The May 9 commemorations come at an extremely sensitive time for the two Slavic nations that fought side by side against Nazi Germany but are now locked in an unprecedented confrontation that threatens to tip Ukraine into civil war.