A group of masked men issued a chilling warning to Jews living in eastern Ukraine this week: register with the government, or face deportation. According to reports from local and Israeli media, the men were seen outside a synagogue in the city of Donetsk on Wednesday, where they were handing out leaflets to people leaving a Passover service. Written on the papers were orders for all Jews over the age of 16 to register their names and property with a governmental office, and to provide documents to "register your Jewish religion."

The identities of the men remain unknown, and it's not clear whether they are affiliated with a particular movement or political party. But the incident has nevertheless rekindled strong memories of World War II-era fascism in Ukraine, where anti-Semitism has become a propaganda chess piece for Russian leaders since the overthrow of President Viktor Yanukovych earlier this year.

Ukraine's fledgling government has struggled to quell unrest in the eastern part of the country, where pro-Russian separatists in Donetsk and other regional capitals have taken control of government buildings. American and European leaders have accused Russia of fueling the protests, claiming that Moscow is using the exact same tactics it deployed in Crimea, which seceded from Ukraine after holding a referendum last month. The Kremlin has said it will defend the interests of the region's large ethnic Russian population, which it sees as under threat, though it has denied any involvement in the separatist movement.

"the true victims are the Jewish communities."

The US was quick to denounce the leaflets distributed this week, while Jewish community leaders in Donetsk said the incident "smells like a provocation."

"In the year 2014, after all of the miles traveled and all of the journey of history, this is not just intolerable — it's grotesque," US Secretary of State John Kerry said this week at a press conference in Geneva. "And any of the people who engage in these kinds of activities — from whatever party or whatever ideology or whatever place they crawl out of — there is no place for that."

The leaflets were allegedly signed by Denis Pushilin, the leader of the new and unrecognized government that pro-Russian separatists have set up in Donetsk, though Pushilin has denied responsibility. Geoffrey Pyatt, the US ambassador to Ukraine, said it appears that the leaflets are "the real deal."

The Anti-Defamation League (ADL), a New York-based non-government organization, questioned the authenticity of the leaflets, though it fears that Ukrainian Jews may be caught in the crosshairs of a still-tense political dispute.

Anti-semitism for political gain

"We have seen a series of cynical and politically manipulative uses and accusations of anti-Semitism in Ukraine over the past year," Abraham Foxman, national director of the ADL, said in a statement. "The perpetrators and their targets are opposing politicians and political movements, but the true victims are the Jewish communities. We strongly condemn the anti-Semitic content, but also all attempts to use anti-Semitism for political purposes."

Russia has gone to great lengths to discredit the new government in Kiev, which it refuses to recognize, with President Vladimir Putin condemning anti-Yanukovych protesters as "nationalists, neo-Nazis, Russophobes and anti-Semites." Some Jewish leaders have supported the Kremlin's narrative, but most have dismissed their claims, accusing Putin of trying to sow deeper discord in Ukraine.

There are more than 260,000 Jews in Ukraine, according to estimates from the Jewish World Congress, making it the third largest Jewish community in Europe. They've had a turbulent history there, as well. Ukrainian Jews were the target of violent pogroms during the 19th century, and faced institutionalized anti-Semitism during Soviet occupation. During the World War II, a Ukrainian nationalist leader named Stepan Bandera worked with the Nazis to both kill Jews and push Russia out of the country. (The fliers distributed this week accused Ukraine's Jews of supporting the new government, which it labeled a "Banderite junta.")

Experts say Ukrainian extremism has been blown out of proportion

But Anton Shekhovtsov, a Ukrainian researcher of European right-wing movements at University College London, says anti-Semitism isn't widespread in eastern Ukraine today. He believes this week's incident is likely an isolated case rather than the start of a dark new chapter.

"People might be anti-Semites but they would not be engaged in anti-Semitic violence or vandalism on a regular basis," Shekhovtsov says. "And on the whole, anti-Semitism in Ukraine is quite low, at least compared to other European countries."

Right-wing groups do have a presence in the new Ukrainian government, though they comprise a minority, and experts say their influence has been vastly blown out of proportion for political purposes. As a result, Ukrainian Jews have found themselves in a precarious situation, caught between the push and pull of East versus West.

"The glass-half-empty response would be, ‘You're damned if you do and you're damned if you don't," says David Shneer, professor of history and Jewish studies at the University of Colorado, Boulder. "And the glass-half-full response would be, ‘We have opportunities here because there's so much change going on right now, I want to be at the table in fostering a future where I have a place at the table.'"