Russia expels Ukraine diplomat in tit-for-tat move

MOSCOW, July 29 (Reuters) - Russia on Wednesday ordered a Ukrainian diplomat to leave the country in what it said was retaliation for Kiev's expulsion last week of a Russian diplomat responsible for the Black Sea Fleet.

Russia's Foreign Ministry said in a statement that it summoned Ukraine's Moscow ambassador on Wednesday to complain of "openly anti-Russian actions." It ordered an adviser in the Ukrainian embassy in Moscow to "immediately end his mission."

Moscow leases a base for the Black Sea Fleet in Sevastopol, a port in the Crimea peninsula which is populated by mainly ethnic Russians. The base has been a thorn in relations between Moscow and Kiev since Ukraine's independence in 1991.

Amid rising tension over the future of the fleet, whose lease is due to expire in 2017, a Russian official based in Ukraine said last week that he was preparing to leave.

Ukrainian police then halted convoys of Russian military vehicles in the town hosting the fleet, in what they said was a violation of a bilateral agreement.

Ties between the countries have also been soured by Ukraine's stalled bid to join the NATO military alliance and disputes over the pricing of Russian gas deliveries to Europe through Ukrainian gas pipelines. (Writing by Conor Humphries; Editing by Jon Boyle)