Moscow: A Russian court on Wednesday sentenced an Estonian policeman to 15 years in jail on espionage charges in a move slammed by the European Union (EU), as tensions spike over the Ukraine crisis.

A court in the western Pskov region, which borders Estonia, sentenced Eston Kohver on charges of spying, weapon possession and illegally crossing the border, his court-appointed lawyer, Yevgeny Aksyonov, said.

Prosecutors claimed Kohver was detained on Russian territory last September as he carried out an undercover operation.

Tallinn, however, accuses Moscow’s FSB security service of kidnapping the law enforcement officer at gunpoint from Estonian territory as he was investigating cross-border crime.

“The abduction of Eston Kohver from the territory of the Republic of Estonia by the FSB on 5 September and his unlawful detainment in Russia thereafter constitute a blatant breach of international law,” Estonian Foreign Minister Marina Kaljurand said in a statement.

“Today’s judgement does not change our position. We call on Russia to immediately release Eston Kohver.”

Tensions between Russia and the ex-Soviet Baltic states have soared over Russia’s seizure of Ukraine’s Crimea peninsula and alleged backing of pro-Russian separatists in eastern Ukraine.

Many in Estonia believe the timing of Kohver’s arrest was deliberate, coming just two days after US President Barack Obama visited Tallinn to trumpet Baltic security following Russia’s role in the Ukraine crisis.

The Estonian foreign minister slammed Kohver’s trial, saying there had been “no fair administration of justice in the proceedings”.

“Our consul was not allowed to be present at the hearings and Eston Kohver was deprived of adequate legal aid,” Kaljurand said.

EU foreign policy chief Federica Mogherini also urged Russia to free Kohver, denouncing his “abduction” as a violation of international law.

“The EU continues to call on the Russian Federation to act according to its international obligations, release Mr Kohver immediately and guarantee his safe return to Estonia,” Mogherini said in a statement.

Baltic states Estonia, Latvia and Lithuania emerged from nearly five decades of Soviet occupation in the early 1990s and joined North Atlantic Treaty Organisation (Nato) and the European Union in 2004 in a bid to shore up their security amid tense relations with Moscow.

Leaders in Eastern Europe have grown increasingly jittery of Russia’s expansionism in Ukraine, with some hawkish voices in the West suggesting Moscow could try to intervene in the Baltics.

The spike in tensions has also seen a rise in spying claims by Moscow and its neighbours, in a series of Cold War-style tit-for-tat incidents.

Russia’s federal security service said in May that it was holding a Lithuanian spy caught “red-handed” in Moscow during an exchange of secret documents.

The announcement came just days after Lithuanian prosecutors said they had detained a Russian citizen suspected of spying.

The European Union and United States have slapped tough economic sanctions on Moscow over the crisis in Ukraine, while Russia has responded by banning Western agricultural produce.

Independent Russian political analyst Masha Lipman said that the lengthy sentence for Kohver was a sign of how bad relations between Moscow and Europe have become.

“The relationship with Europe has already hit its lowest level in the post-Soviet period,” Lipman said.

“This move exacerbates the confrontation between Russia and the EU.”