A Ukrainian court has ruled that the country should take control of 22 lighthouses in Crimea operated by the Russian military.
Crimea's lighthouses have long been a source of tension
Ukraine says a 1997 deal with Russia on division of the Black Sea Fleet gives it ownership of the lighthouses.
Moscow says they have been leased to the Russian navy until 2017.
Arguments about the Soviet-era Black Sea Fleet have soured Russian-Ukrainian relations since the collapse of the USSR in 1991.
The Sevastopol appeals court decided on Tuesday to transfer responsibility for the 22 lighthouses from the Russian defence ministry to the Ukrainian transport ministry.
Kiev says the Russian navy illegally controls the sites. In 1998, the Ukrainian government decided that they should come under the control of its transport ministry.
Moscow says the lighthouses were leased to its navy under the 1997 agreement and that they are crucial for the safety of the Black Sea Fleet.
Kiev says all maritime installations and navigational equipment on the Crimean coast are the property of Ukraine.
The Ukrainian foreign ministry has previously accused the Black Sea Fleet of violating the terms of their long-standing agreement by refusing to hand over navigational facilities.