In a worrying development that epitomizes the new policy of assertiveness in Eastern Europe, Russia has taken custody of an Estonian intelligence officer, further ratcheting up tensions in a region already on edge over Russia's actions in Ukraine.

Vox reports that Estonia and Russia are giving two different versions of the events that led to an Estonian intelligence officer ending up in Russian custody.

Unlike its actions in Ukraine, Russia has not denied that they have the Estonian operative in custody.

Vox says that the incident took place near a border crossing on the joint Russian and Estonian border at the Luhamaa Crossing. That is where the agreement between both countries ends.

Estonia claims that the officer was kidnapped from the Estonian side of the border while on assignment. The officer was described as being involved in counter intelligence and organized crime. Vox notes Estonia did not elaborate in what capacity he was working at the time of the incident.

Estonia says the crossing had its radio and cell phone communications jammed while smoke grenades were deployed.

Russia denies that version of events. Russia claims they apprehended the agent as he worked on their side of the border. They say he was in possession of 5,000 Euros, a gun, and material suggestive of intelligence operations.

The incident occurred less than two days after U.S. President Barack Obama was in the Estonian capital to reassure Estonia and the other Baltic nations that the United States and NATO alliance, of which they are members, would defend them from Russian aggression.

Russia views those nations' membership in NATO as a threat to its dominance in the region, and is a major motivation behind Russia's contemporary foreign policy.

Estonia, like Ukraine, has a large population of Russian speakers and those who identify with Russian culture. Vox notes that Estonia's proportion of Russian speakers is even greater than Ukraine's, and stands at around 25 percent.