Romania ordered a Russian diplomat out of the country Tuesday in a tit-for-tat expulsion for the arrest of an alleged Romanian spy in Moscow, dpa reported.
The foreign ministry said the first secretary at the Russian ambassy in Bucharest had been declared persona non grata and given 48 hours to leave the country.
Earlier the ministry protested at the arrest of one of its diplomats on espionage charges in Moscow, threatening to take the "necessary steps" over what it said was a violation of the Geneva Convention protecting the immunity of diplomats.
In a note handed to the Russian embassy in Bucharest, the ministry complained of the "completely inappropriate treatment" of its diplomat and the way in which the incident was presented to Russian media.
The Russian intelligence service (FSB) said Monday it had arrested Gabriel Grecu as he attempted to buy military secrets from a Russian citizen.
The diplomat had worked as the first secretary in the political department of the Romanian embassy, but was actually a member of the Romanian secret service, the FSB said.
"Items of spying equipment that fully reveal his hostile activity against Russia have been confiscated from the intelligence officer," the FSB said in a statement.
The diplomat was declared persona non grata and ordered to leave Russia within 48 hours.
Bucharest and Moscow have traditionally had an uneasy relationship. This has worsened since Romania, a former Warsaw Pact country, joined NATO in 2004 and particularly since its open efforts to Westernize its neighbour, the former Soviet republic Moldova.