"I'm here to prevent any provocations from the fascists. I served in a self-defence unit during March, and I consider it my duty to be here," said Natalya Malyarchuk, 52, a resident of Sevastopol, wearing a red arm band saying "Patrol."
The ethnic Russian majority among Crimea's two million population broadly welcomed the Russian takeover that came in the wake of the Kiev uprising. Given by Soviet leaders to Ukraine only in the 1950s, many Russians long saw it as rightfully theirs. Western powers have imposed sanctions against Russia in response, but reactions have been muted.
While Putin's redrawing of European borders has sparked great alarm across the continent, U.S. and European leaders are concerned not to harm their own economies by isolating Moscow.
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And there is little popular support in the West for an armed conflict with Russia on behalf of Ukraine, a country that is not a member of NATO and where successive leaders have left a legacy of massive corruption, poverty and feeble state institutions.
In Sevastopol, factory worker Vasily Topol, 31, wearing a white T-shirt with an image of Putin in sunglasses and the words "Russia's Army", said life was better since becoming Russian.
"We have the greatest admiration for Putin, we are morally and materially better off since Crimea became part of Russia," he said, speaking on an embankment overlooking Russian warships.
"My salary has risen by two and a half times."
In Slaviansk, the military stronghold of the separatists in eastern Ukraine, separatist "people's mayor" Vyacheslav Ponomaryov and a guard of militiamen led a march of around 2,000 people to lay flowers at a memorial to the World War Two dead.
Veteran Anatoly Strizhakov said: "Look at all these people - the children, the women, the pensioners. We're all here, ready for anything ... Today shows we've got the spirit to stand up to whatever the Ukrainians are planning."
Ponomaryov, who fired a pistol three times in the air during the ceremony, reassured people it would be safe to vote on Sunday. Larissa Kurennaya said of the veterans to whom she was giving lilac and red carnations under a statue of Lenin:
"They are a reminder that war must be avoided at all costs ... We will never surrender to the Ukrainians but this referendum could help resolve the situation peacefully.
"I'm voting for the republic and so is everyone I know."
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Voters in the two regions, with a combined population of over 6 million, will be asked to vote Yes to the secession of self-styled "People's Republics" in Donetsk and Luhansk.
Opinion polls in recent months have indicated that support for such a move is far from solid and it is unclear how many people will actually take part in voting. A referendum in Crimea in March, which many boycotted, backed secession by 97 percent.
As he headed to the parade in Slaviansk, his blue uniform weighed down by Soviet medals, 86-year-old veteran Alexander Fyodorovich, said: "There's not much cause for celebration.
"The Ukrainians are at the gates and there are barricades on almost every road in town. I just want peace - I don't care about Ukrainians, Russians or anything.
"We need to sort this out without more bloodshed."