Voter turnout in Crimea was estimated at about 64 percent Sunday as polls closed after the vote on a referendum for the eastern Ukrainian region to break away and become a part of Russia.
The United States, the European Union, and the European Council all released statements Sunday calling the referendum illegal and illegitimate, and warning its outcome will not be recognized internationally.
The regional Crimean government has said to expect a preliminary result of the vote later Sunday .
Meanwhile, U.S. Secretary of State John Kerry and Russian foreign minister Sergei Lavrov on Sunday agreed to push for Ukrainian constitutional reforms for power sharing and decentralization as a solution to its political crisis.
During a phone call Sunday, Kerry also told Lavrov the United States will not recognize the referendum.
Reuters news service reports Ukrainian Prime Minister Arseny Yatsenyuk is vowing to track down those promoting separatism in Crimea. He said Ukraine will find all ringleaders of separatism who are trying to destroy Ukrainian independence.
Also in Kyiv, Ukraine's acting defense minister told reporters the defense ministries of Ukraine and Russia have agreed on a truce in Crimea until March 21.
Defense Minister Ihor Tenyukh said an agreement has been reached with Russia's Black Sea fleet, which is stationed in Crimea, that no measure will be taken against Ukrainian military facilities during the truce. He said Urkaine's military sites are now replenishing their supplies.
During a phone call with Russian President Vladimir Putin, German Chancellor Angela Merkel proposed an Organization for Security and Cooperation in Europe mission in Ukraine be expanded immediately.
Crimea is a primarily ethnic-Russian majority region of Ukraine. Moscow says it has the right to protect its interests in Crimea.
Ukraine's Foreign Ministry said Saturday Russian forces have seized the Ukrainian village of Strilkove, near the Crimean border.
There are no reports of shots being fired, but the Ministry calls the takeover an "invasion" and demands the Russian soldiers leave. Ukrainian border guards say the Russians are guarding a gas pumping station in the town.