Russia has told two Ukrainian diplomats to leave the country in retaliation for moves by Kiev against two Russians.
The dispute underlines the tensions between Russia and neighbouring Ukraine, whose leaders seek closer integration with the West.
Ukraine told the two diplomats to leave this week, after weapons movements by the Russian Black Sea Fleet that Ukraine said were not permitted. The fleet is based in Ukraine's port of Odessa.
A Russian Foreign Ministry statement yesterday said that Ukraine had halted the expulsion of one of the diplomats but still considered Kiev's actions "an openly anti-Russian step."
It says Ukraine's consul-general in St Petersburg and a counselor at the Ukrainian embassy were being asked to leave.