BELGRADE, Serbia -- Serbia is investigating reports of an alleged spying affair involving Russia, sparked by a video posted on social media, officials said Wednesday.

The military intelligence agency has been instructed to look into reports that an alleged Russian military intelligence agent was filmed bribing a senior member of Serbia's security service, Prime Minister Ana Brnabic said.

"I am expecting new information," said Brnabic. "I am in contact with the president. If true, it is a serious problem."

The video of the alleged bribery was posted on YouTube on Nov. 17. It apparently shows the Russian diplomat giving the Serbian agent a bag during a meeting in Belgrade. Later, the Serbian takes out an envelope with money from what seems like the same bag.

Serbia's state television reported that Serbia's intelligence agency has confirmed the authenticity of the video. Relja Zeljski, an analyst at the Security Intelligence Agency, told the broadcaster that it has been confirmed that a Russian agent is featured in the video.

Zeljski, however, refused to elaborate on the identity of the alleged Serbian agent, whose face is blurred in the video. Officials said more information would be available after a meeting on Thursday of Serbia's national security council, a top state security body.

Serbia's Defence Minister Aleksandar Vulin told the Tanjug news agency that the "situation is very serious." He suggested the affair was linked to Serbia's decision to remain militarily neutral despite most countries in the Balkan region joining NATO.

Serbia is seeking membership in the European Union but maintains close ties with Russia. A rare ally of Moscow in Europe, Serbia has vowed to stay out of NATO and has refused to join Western sanctions against Russia over its actions in Ukraine.