The demand came as U.S. President Barack Obama prepared to meet Wednesday with Ukranian Prime Minister Arseny Yatsenyuk.
Vladimir Konstantinov, speaking in Moscow, said the approximately 3,500 Ukrainian troops should leave "quietly and peacefully," the New York Times reported.
An unidentified official, speaking in Crimea's regional capital of Sevastopol announced a plan to build a railway bridge connecting Crimea with mainland Russia, bypassing Ukraine.
Also Sunday, a statement from the Kremlin said Russian President Vladimir Putin told German Chancellor Angela Merkel and British Prime Minister David Cameron plans for a referendum vote next Sunday on the Crimean regional assembly's vote to secede from Ukraine and join Russia "are based on the norms of international law, and aim to endure the legal interests of the population of the peninsula."
In Sevastopol, Pavel Dorokhin, deputy chair of the committee on industry of Russia's parliament, said Russia has set aside 40 billion rubles ($1.1 billion) to rebuild Crimea's infrastructure.
The White House announced in a statement Sunday Yatsenyuk will visit Washington Wednesday. The statement said his visit is intended to highlight U.S. support for the people of Ukraine.
The Ukrainian Embassy in Washington said Crimea is part of the Ukraine and Kiev won't bow to outside pressure over its future but the bigger issue is what rules the world will apply.
"Ukraine is under attack -- blatant and unprovoked," the embassy said in a statement issued Saturday. "The Crimean peninsula, an integral part of Ukraine, is being occupied by foreign troops."
The statement said the legitimate government in the autonomous, pro-Crimea region was ousted and a man "with criminal background was installed as a puppet prime minister."
"Being aware that their time is short-lived, the criminal junta called out a referendum that is to be conducted within 10 days," the statement said of next Sunday's referendum to secede from Ukraine and join the Russian Federation. "There is no doubt about the 'results' to be achieved at gunpoint of the aggressor and in violation of Ukrainian and international laws."
"We won't accept any kind of staged 'referendum' under the guns of an aggressor. We will never give up on Crimea and never put up with this kind of violent behavior," the statement said.
"If this can be done to Ukraine -- anything can be done to anyone," the statement said.
In an appeal to Russia, the Ukrainian Embassy asked that it not "destroy the bonds that connect our peoples! Don't create another hotbed of tension in your surroundings!"
Ukraine is prepared to talk with Russia and involve international negotiators.
"But there is one thing for which Ukraine will never be ready -- to give in to aggression," the statement said. "We will never budge. We will never compromise our sovereignty."
The embassy also appealed to the international community.
"For it's not only about Ukraine. It's about the rules the world abides by," the statement said.
The ballot for Crimean referendum offers voters two choices: Join Russia or become independent, the Kiev Post reported.
The Crimean Parliament released the design of the ballot that asks voters to check a box for one of these two questions: "Do you support joining Crimea with the Russian Federation as a subject of Russian Federation?" or "Do you support restoration of 1992 Crimean Constitution and Crimea's status as a part of Ukraine?"
There is no "no" option.
In Kiev, acting President Oleksandr Turchynov rejected the referendum as illegal and unconstitutional, but pro-Moscow Crimean authorities who seized power on the peninsula Feb. 27 said they don't recognize the central government as legitimate and will go ahead with the vote.
Thousands of troops seized control of buildings, roads and Ukrainian military bases in the peninsula last week. While Russian President Vladimir Putin has denied the troops are Russian, media outlets have reported the troops have been seen driving in vehicles with Russian military license plates.
Mykhailo Malyshev, head of the Crimean Parliament's referendum commission, said the election will have 1,250 polling stations, the Post said.
Malyshev also said 2.5 million ballots will be printed. The Post, citing Central Election Commission data, reported that as of Feb. 28 there were more than 1.5 million voters in Crimea.
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