Parliament in Ukraine's autonomous Crimean Republic has dismissed the republic's government and scheduled a vote on the peninsula's future.
In an extraordinary session on February 27, lawmakers voted that Prime Minister Anatoliy Mohyliov's government had not performed satisfactorily.
Lawmakers also approved holding a referendum asking whether Crimea's autonomy from Ukraine's central government should be strengthened.
The referendum asks citizens to vote yes or no on the statement: "The Autonomous Republic of Crimea has state independence and is a part of Ukraine on the basis of agreements and accords."
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The referendum is scheduled for May 25 -- the same day that Ukraine's new authorities have designated for a presidential election to replace ousted President Viktor Yanukovych.
Tensions have soared in Crimea, where many residents are pro-Russian, since the ouster of Yanukovych. The peninsula's largest city, Sevastopol, is home to Russia's Black Sea Fleet.
PHOTO GALLERY: Pro- and anti-Russian demonstrators clashed in Simferopol on February 26.
Early on February 27, armed pro-Russian demonstrators seized key government buildings in the capital, Simferopol and raised the Russian flag. A delegation of Russian State Duma deputies has been in Crimea meeting with locals and officials.
In Kyiv, newly confirmed Prime Minister Arseniy Yatsenyuk said the new government will resist separatism.
"We are committed to the territorial integrity and unity of my country. And the new government will do everything and use all legal means to stabilize the situation in Crimea and to convince the entire world and all Ukrainian neighbors that Ukraine is a sovereign united country and no separatism is allowed," Yatsenyuk said.
NATO Secretary-General Anders Fogh Rasmussen said in Brussels that NATO has no reason to worry that a Russian military exercise that began on February 26 in western Russia is linked to developments in Ukraine. But he acknowledged Russia's timing has attracted attention.
"We have no information indicating that Russia has any plans to intervene militarily. In my statement today, I have been very balanced and urged all parties, on all sides, not to take steps that can escalate the situation. On the contrary, we need steps that can cool down the whole situation," Rasmussen said.
WATCH: Large crowds react to the announcement of individual ministers on Kyiv's Independence Square on February 26.
U.S. Defense Secretary Chuck Hagel said Washington is "closely watching" the Russian exercise. He called on Moscow not to take any steps that could be misinterpreted or, as he put it, "lead to miscalculation during a delicate time."
"Today I affirmed America's strong support for Ukraine's territorial integrity and sovereignty and NATO defense ministers made the same declaration in a joint statement. We expect other nations to respect Ukraine's sovereignty and avoid provocative actions," Hagel said.
White House spokesman Jay Carney echoed Hagel's comments in Washington.
Russian Deputy Defense Minister Anatoly Antonov said in Moscow that the activities of forces of the Black Sea Fleet are normal and being conducted under the terms of the basing agreement.
He called on "external and internal" actors "not to destabilize the already-complicated situation" in Crimea.
Russian Foreign Minister Sergei Lavrov and U.S. Secretary of State John Kerry discussed the situation in Ukraine by telephone on Thursday.
With reporting by Reuters, AP, AFP, UNIAN, and Pravda.con.ua