Montenegro protests after senior politician held while changing planes at a Moscow airport

Montenegro on Monday strongly protested "inappropriate" conduct by Russian authorities against a senior ruling party leader who was prevented from changing planes at a Moscow airport.

Lawmaker Miodrag Vukovic said he was kept overnight in a transit zone at Domodedovo International Airport while on his way to an international meeting in Belarus. He returned to Montenegro on Monday.

The Montenegrin Foreign Ministry summoned the Russian ambassador, telling him the incident "represents a breach of basic international rules and diplomatic practices."

Russian Foreign Ministry spokeswoman Maria Zakharova said the Kremlin imposed the ban against Vukovic because Montenegro had joined Western sanctions against Moscow over its actions in Ukraine.

"It's not a secret that Montenegro joined the European Union's anti-Russian sanctions, including against (Russian) individuals," Zakharova said on the Foreign Ministry's website.

"We have always said that we reserve the right to take retaliatory measures on the basis of reciprocity, as is customary in diplomacy," she said. "We will provide a relevant explanation to the Montenegrin side."

Vukovic said the incident was politically motivated.

Montenegro previously was a close ally of Russia, but is set to become NATO's 29th member in June. Russia has threatened economic and political retaliation against the small nation.

Montenegro says that Russia was behind a foiled coup attempt in October to prevent it from joining NATO, which Moscow denies.