BAKCHISARAY, Ukraine (Reuters) - For Sofiya, an elderly museum curator and an ethnic Tatar watching over a collection of Scythian gold inside an Ottoman palace once inhabited by Crimea's Muslim Tatar rulers, distrust of the Russians runs deep.

She frowns as she recalls her grandmother telling her about the day Soviet soldiers came to their home outside Simferopol, the Crimean capital, almost 70 years ago, rounded everyone up, and deported them to Central Asia.

The fact that Russians living in Crimea at the time later crept into the Tatars' empty homes and appropriated them for themselves still rankles.

"The Russians said they were afraid to enter our homes and barns for days afterwards," Sofiya told Reuters, referring to May 18, 1944, the day when Soviet soldiers rounded up Crimea's Tatars and deported them en masse to Central Asia to punish them for collaborating with Nazi Germany.

"But they did enter our homes and then they kept them. For us, the Russians are the same as the Soviets. They promise us a lot, but later, when we're under their control, they will silence us", she said, demonstratively placing her palm across her mouth.

Seven decades on, Sofiya, who declined to provide her surname, and many other Tatars, Sunni Muslims of Turkic origin, say they are apprehensive about the prospect of Crimea leaving Ukraine and becoming part of Russia in a referendum this Sunday.

Making up an estimated 12 percent of Crimea's population of 2 million, the Tatars are more forthright when it comes to asserting their rights than the peninsula's ethnic Ukrainians and have clashed with police and Russians in the past.

Worried they might disrupt Crimea's transition to Russian from Ukrainian control, the Kremlin and the peninsula's Russian-backed authorities have been working hard to win them over, even inviting one of their spiritual leaders to a meeting with Russian President Vladimir Putin in Moscow.

Crimea's pro-Russian authorities have held out the promise of guaranteed Tatar representation in the local government, proper land ownership rights - something many Tatars lack - and financial aid. They have also pledged to extend gas supplies to remote Tatar areas.

In an interview with Reuters on Thursday, Sergei Aksyonov, the leader of Crimea's separatist authorities, played down the idea that the Tatars were unhappy.

"We have always had constructive dialogue with the Tatars," he said. "Financing for Crimean Tatars will be doubled this year ... It is all calm on the streets. There are no ethnic or religious conflicts and we will never allow that."

But some Tatars say they have received veiled threats. In a disturbing echo of their 1944 deportation, unidentified individuals scrawled crosses on a small number of gates at Tatar-owned properties in Bakchisaray and Simferopol, the Crimean capital. The marks were swiftly scrubbed off.

Some Tatars say they have been verbally abused on public transport. Others speak of seeing unfriendly men walking around with baseball bats. Some worried locals have even set up security patrols to protect their loved ones and their homes.

PERSECUTION

The Tatars, around 250,000 of whom live in modern-day Crimea, have lived through turbulent times. In 1897, census data showed they made up more than a third of Crimea's population.

In their heyday, from the 15th to the 18th century, they ran a Crimean Khanate. It became notorious for enslaving Christian Slavs and selling them on within the Ottoman Empire, something Russian nationalists recall to this day.

With the soaring minaret of its mosque and elaborate Ottoman-style interiors, the 16th century palace at Bakchisaray, where Sofiya works, is one of the few remnants of the period.

Russian Empress Catherine the Great ended Tatar domination in Crimea when she conquered it at the end of the 18th century. Many Tatars were massacred or exiled. Others fled.

Later, the Soviet Union brought more hardship. Many prominent Tatars were arrested and executed in Soviet dictator Josef Stalin's purges and harsh agricultural collectivisation policies led to famine.

Between 1917 and 1933, historians estimate that half the Crimean Tatar population died, was killed or deported.

Things became no easier with the advent of World War Two. Though many Tatar men served in the Red Army and fought the Nazis - sometimes with distinction - others joined special units of the Waffen SS. When Soviet troops retook the peninsula, Stalin took his wrath out on the entire Tatar population.

In a single day, Soviet troops rounded everyone up, loaded them into railway cattle cars and sent nearly 200,000 into exile in Central Asia. Many died en route. Others died of malaria or starvation when they arrived.

When Mikhail Gorbachev, the last Soviet leader, finally allowed the Tatars to start returning to Crimea in the 1980s, those who came back found they could not get their homes back and that no one wanted to hire them.

'THE ENEMY'

Sofiya, 64, who says she, her mother, her husband and her three sons only returned from exile in Uzbekistan in 1985, recalls the period with dread.

"We were treated like the enemy," she said.

She recalled how a policeman tried to get them to go back to Central Asia, that they were forced to live six to a room, and that her husband was offered a job only to have it withdrawn once his employer discovered he was a Tatar.

"Nobody was waiting for us. Nobody wanted us."

But in time, she says her family and others slowly rebuilt their lives, buying up old shacks that Russians and Ukrainians didn't want to live in, and doing any job, no matter how menial, to make their way.

Now, she and others say, the Tatars fear new upheaval.

Saliya Fatanjiyeva, 60, a fellow museum curator, cuts into the conversation at this point, her voice taut with emotion.

"We've spent 25 years getting back on our feet here," she said. "Twenty-five years winning the Ukrainians' trust and now it looks like we'll need to start all over again proving ourselves to the Russians."

There would probably be a redistribution of property rights, she said. Both women, like other Tatars interviewed by Reuters, said they would not take part in Sunday's referendum.

"The only reason we came back in the first place is because this is our homeland," said Fatanjiyeva. "We're not going to leave again. They'll need to use bulldozers to get rid of us this time."

Link to Crimean Tatar census data: http://link.reuters.com/zyj67v (Editing by Ron Popeski)