Tatars in Crimea are commemorating 70 years since their deportation by Soviet leader Josef Stalin.
On the outskirts of Crimea's capital, Simferopol, at least 10,000 people participated in a rally, carrying placards calling for "self-determination"
The press service of the Mejlis, the Crimean Tatars' main representative body, said a resolution was adopted calling for "territorial autonomy" for the community, Tatar representatives in the Crimean government, and "an end to discrimination against and the repression of the Tatars of Crimea."
There was a heavy police presence in Simferopol, with two loud military helicopters flying low over the rally.
Earlier in the day, dozens of people gathered at a memorial near Simferopol’s railway station, the deportation point for thousands of Tatars sent into internal exile.
Several hundred people also marched in Ukraine's capital, Kyiv.
Speaking to journalists in Kyiv, Crimean Tatar leader Mustafa Dzhemilev said, "This year, the situation [of Tatars in Crimea] is almost the same as it used to be during the Soviet regime.”
Dzhemilev is banned by de facto Russian authorities in Crimea from returning to the peninsula.
Tens of thousands usually gather for a rally marking the day on May 18, 1944, when Soviet authorities began deporting Crimean Tatars to Central Asia. Many of the 200,000 deportees died on their way into exile.
But the Mejlis announced that the rally had been called off and that "no mass rallies will take place in the center of Simferopol" on May 18, and called instead for Tatars to gather at religious centers and other locations
The move came a day after the de facto authorities in Crimea, annexed by Russia in March, banned all public gatherings until June 6.
Pro-Moscow Crimean leader Sergei Aksyonov cited violence in southeast Ukraine as the reason for his decision to ban the rally.
Refat Chubarov, chairman of the Mejlis, described the decree as an "inhuman act."
Russian President Vladimir Putin met with representatives of the Crimean Tatars in Sochi, southern Russia, on May 17 and said Russia would improve their lives.
But he added that they must accept that their future lay with Russia.
In Washington, U.S. Secretary of State John Kerry said, "Russia's occupation and illegal attempt to annex Crimea has reopened old wounds."
Kerry said the United States will "commemorate the tragedy of 1944 with heavy hearts, even as we stand in solidarity with Crimean Tatars today against a new threat to their community."
Meanwhile, a leader of the self-declared "Donetsk People's Republic," a pro-Russian separatist group in eastern Ukraine, has announced there will be parliamentary elections in the region on September 14.
Denis Pushilin, told a crowd of some 1,000 people at a public meeting on Lenin Square in the city of Donetsk on May 18 that "each of you will be involved" in the elections.
Pushilin did not clarify how they would be involved.
Near the eastern Ukrainian town of Slovyansk, fighting was reported overnight.
Russian media quoted pro-Russian separatist fighters in the area as saying they sustained casualties, including several killed.
Ukraine's UNIAN news agency reported that four Ukrainian troops were wounded. Ukrainian Interior Minister Arsen Avakov said one "terrorist" was killed.
With reporting by ITAR-TASS, Interfax, and UNIAN