Vladimir Masorin, the commander in chief of Russia's navy was quoted by Interfax news agency as saying: "The position of the Russian naval headquarters is firm: the Yalta lighthouse must be returned to Russian hydrography services and must function normally in order to ensure the security of navigation in the Black Sea region,"
"I have given the order to the commander of the Black Sea fleet to take back control of the lighthouse, by use of methods of civilized discussion."
A Russian navy spokesman said that a group of seven unidentified people had tried to enter another lighthouse in Crimea. The report offered no further details and could not be immediately confirmed.
'No legal basis'
Ukraine's foreign minister, Boris Tarasyuk, insisted that lighthouses in Crimea belonged to Kiev.
"You can't seize something that's yours," he told Interfax. "Russia has unlawfully held onto all hydrographic sites... There is no legal basis for Russia to insist that these sites are part of the Black Sea fleet."
A top foreign ministry official later told reporters that Russia today "unlawfully" controls 35 out of the 100 hydrographic sites in Crimea.
Russia accused Ukraine of "seizing" the Yalta lighthouse during a maintenance session on Friday.
Captain Igor Dygalo, a Russian navy spokesman, said that in a move of "pure provocation," an eight-member team from the Ukrainian transport ministry "illegally entered the Yalta lighthouse under the pretext of maintaining the site and equipment, and then blocked access to Russian personnel."
The dispute over the lighthouse is the latest episode in an ongoing dispute over Moscow's lease of Ukrainian territory for its Black Sea fleet.
Under a lease agreement signed in 1997, Moscow pays Kiev just under 100 million US dollars annually to lease land and property for its Black Sea headquarters in Sevastopol, the southern Crimean port where the fleet was based during the Soviet era.
The latest spat also comes after Russia recently imposed a price hike on its natural gas sales to Ukraine.
During the standoff over the gas price, Ukraine suggested that it could put up the cost of lease payments to bring them in line with what other governments pay to house military bases abroad. Russia has said the lease cannot be revised.
The gas dispute caused concern
Russia earlier this month cut gas supplies to Ukraine after sharply hiking its rates and triggering panic throughout Europe, which relies on Russian gas shipped through Ukrainian pipelines.
The two countries quickly agreed on a complex new deal on 4 January 4 that virtually doubles Kiev's rates but leaves them far below Moscow's original demand of a four-fold hike. The agreement has been fiercely condemned by Ukraine's political opposition.
Relations between Russia and Ukraine have deteriorated after the 2004 "orange revolution" presidential election saw Viktor Yushchenko, who has vowed to drive the ex-Soviet republic toward membership of the European Union and NATO, defeat the Moscow-backed candidate Viktor Yanukovych.