Summary West considers the elections as crucial to restore legitimacy to leaders of former Soviet republic.
WASHINGTON (AFP) - The United States on Tuesday denounced moves by pro-Russian separatist groups in eastern Ukraine to organize what it called a "bogus" referendum.
Comparing Sunday's plebiscite to an earlier vote that preceded Moscow's annexation of Crimea, State Department spokeswoman Jen Psaki said: "This is the Crimea play-book all over again."
"The United States notes with concern efforts by pro-Russian separatists in Donetsk and Luhansk to organize a bogus independence referendum ," Psaki told reporters.
Kiev and its Western backers see Moscow's main aims as making sure the planned "referendum" goes ahead, while sabotaging nationwide presidential election due to be held two weeks later.
The West considers the May 25 presidential elections as crucial to restoring legitimacy to the leaders of the former Soviet republic, who were installed by the parliament after pro-Moscow president Viktor Yanukovych fled in the face of widespread pro-democracy protest.
Assistant Secretary for Europe Victoria Nuland said the presidential elections on May 25 will be "the most pluralistic election that there has ever been in Ukraine" with some parties fielding more than one candidate after splits.
"And far more pluralistic than anything that's been seen in Russia."
But she voiced concerns about whether the people in eastern Ukraine would "have the chance to vote for their candidate" given the tensions on the ground with pro-Russia militias controlling several towns.
The OSCE was expected to send in 1,000 observers and the US was supporting a further 3,000 observers, she said.
"This will be the best observed transatlantic elections for many, many years," Nuland said, speaking at the US Institute of Peace think-tank.
Psaki also warned that "if Russia takes the next step" to move into eastern Ukraine and annex it, "harsh EU and US sanctions will follow."
Russian President Vladimir Putin has so far held off ordering an invasion to "protect" Ukraine's Russian-speaking population although Moscow claims to be receiving "thousands" of calls for help from eastern Ukraine.
Still, Putin has kept an estimated 40,000 troops on the border for the past two months.
Psaki's comments came as Russia rejected a new peace initiative amid mounting fears of open war.
Nearly 90 people have died in less than a week: half around the eastern town of Slavyansk, held by rebels since early April; and half in the southern port city of Odessa, where clashes culminated in a deadly inferno last Friday. Most of those killed have been pro-Russian fighters and activists.
