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Three people were killed in a gunfight and rebels set a police station on fire in eastern Ukraine Friday, as Russian President Vladimir Putin hailed the return of Crimea to Russia in a military celebration marking victory over Nazi Germany.

Tens of thousands gathered in the Crimean port of Sevastopol to hear Putin speak, in his first trip to the Black Sea peninsula since its annexation in March. Putin called Russia’s incorporation of Crimea a "return to the Motherland" and a tribute to the "historical justice and the memory of our ancestors."

Ukraine and members of NATO quickly condemned Putin’s visit. The U.S. called it “provocative and unnecessary.”

“Crimea belongs to Ukraine and we don't recognize, of course, the illegal and illegitimate steps by Russia in that regard,'' State Department spokeswoman Jen Psaki told reporters Friday.

Ukraine's Foreign Ministry protested Putin's appearance in Crimea as trampling on Ukraine's sovereignty and international law, comments echoed by NATO Secretary General Anders Fogh Rasmussen.

"We consider the Russian annexation of Crimea to be illegal, illegitimate and we don't recognize it," Fogh Rasmussen told reporters in Tallinn, Estonia. "We still consider Crimea as Ukrainian territory and from my knowledge the Ukrainian authorities haven't invited Putin to visit Crimea, so from that point of view his visit to Crimea is inappropriate."

Putin didn’t mention the deadly fighting that continues in eastern Ukraine in a speech before the parade, focusing on the historic importance of the victory over Nazi Germany.

Pro-Russia insurgents are fighting the government in Kiev and preparing to hold a referendum Sunday on secession.

At least three people were killed Friday in a clash between government forces and rebels in the eastern Ukrainian city of Mariupol and insurgents set fire to the police station in the Azov Sea city. An Associated Press journalist saw three dead bodies near the station, including one policeman.

The Donetsk regional administration said in a statement carried by the Russian RIA Novosti news agency that 3 people were killed and 25 wounded during the fighting.

But Ukraine's Interior Minister Arsen Avakov said in a statement that 20 "terrorists" and one police officer were killed in fighting that erupted when 60 gunmen tried to capture the police station. He said they were rebuffed by police and the military.

The West and the Ukrainian government accuse Russia of fomenting the unrest in Ukraine's east, where insurgents have seized government buildings in a dozen of cities and fought with government troops. They set a referendum on independence for Sunday, a vote similar to a plebiscite that paved way for Moscow's annexation of Ukraine's Black Sea region of Crimea in March.

Putin's surprise call on Wednesday for delaying the referendum in eastern Ukraine appeared to reflect Russia's desire to distance itself from the separatists as it bargains with the West over a settlement to the Ukrainian crisis.

But insurgents in the Russian-speaking east defied Putin's call and said they would go ahead with the referendum. While reflecting the anger against the central government shared by many in the east, the move also supported Moscow's denial of engineering the mutiny.

Back in Sevastopol, Putin boarded a boat to sail past a line of Russian Black Sea Fleet ships anchored in Sevastopol's bay and greeted their crews before watching a flyby of 70 military aircraft.  Residents flooded the city's streets to watch.

There were more Victory Day celebrations in Moscow’s Red Square Friday as large crowds came to watch military parades.  Earlier in the day, Putin watched as about 11,000 Russian troops proudly marched across Red Square to the tunes of marches and patriotic songs. They were followed by columns of dozens of tanks and rocket launchers as 70 combat aircraft, including giant nuclear-capable strategic bombers, roared overhead.

In another sign of triumph, parading troops on Red Square included a marine unit from the Black Sea Fleet, which flew the Crimean flag on its armored personnel carriers.

Victory Day is Russia's most important secular holiday and a key element of the country's national identity, honoring the armed forces and the millions who died in World War II.

Putin also said Russia had withdrawn its forces from the Ukrainian border, but Pentagon spokesman Rear Admral John Kirby said Friday there had been no evidence of a pullback.

“We've seen no indications that Russian forces have been removed from the border area with Ukraine - eastern and southern Ukraine. So I know what's been said, I've seen the comments by President Putin and other officials in Moscow. We haven't' seen that indication. They're still there in great number, they're still capable, our assessment is it's still a very ready force,” Kirby told reporters.

The United States and the European Union have slapped travel bans and asset freezes on members of Putin's entourage in response to Russia's annexation of Ukraine's Black Sea region of Crimea.

Despite the sanctions, Putin is set to travel to France in early June for a ceremony marking the 70th anniversary of the D-Day invasion that hastened the end of World War II, his first encounter with Western leaders since the start of the Ukrainian crisis.

The Associated Press contributed to this report.