A leading member of the European Parliament says Russian authorities barred her from entering the country despite having a valid diplomatic passport.

German MEP Rebecca Harms, a frequent critic of Russian President Vladimir Putin, said Friday that border guards kept her for three hours at Moscow airport and told her she had been declared persona non grata.

Harms, a co-president of Parliament's pro-environment Greens caucus, took the next plane back to Brussels on Thursday after being refused entry.

The 28-nation EU condemned Russia's decision and accused Moscow of a "regrettable" lack of transparency in blacklisting people.

EU foreign policy spokeswoman Maja Kocijancic said the decision blocked Harms from participating as an observer in the espionage trial of a Ukrainian military officer even though Harms "checked with the Russian authorities before traveling."

The officer, Nadezhda Savchenko, was taken prisoner by pro-Russia rebels in June during fighting in eastern Ukraine and later moved to Russia where she was detained on charges of involvement in the killing of two Russian journalists.

Kiev has demanded her release.


Vladimir Isachenkov contributed from Moscow.