MOSCOW - Russia on Wednesday sentenced an Estonian intelligence officer to 15 years in jail, drawing EU ire after Tallinn said he was kidnapped at gunpoint on its territory.

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, told AFP. Prosecutors said Kohver was detained in Russian territory as he carried out an undercover operation. But Tallinn accused Moscow of kidnapping him 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.

"We call on Russia to immediately release Eston Kohver." Estonia's internal security service covers several fields including counter-intelligence work and weapons smuggling. Tensions between Russia and the ex-Soviet Baltic states have soared over Russia's seizure of Ukraine's Crimean peninsula and alleged backing of pro-Russian separatists in eastern Ukraine. Many Estonians believe the timing of Kohver's arrest was deliberate, coming just two days after US President Barack Obama visited Tallinn in a show of support for Baltic security following Russia's role in the Ukraine crisis.

Kaljurand denounced the trial as unfair, saying Kohver had been deprived of "adequate legal aid" and that the Estonian consul had not been permitted to attend the hearings. In a post on Facebook, Estonian President Toomas Hendrik Ilves asked people to wear yellow ribbons in a show of support for Kohver, who is expected to be sent to one of Russia's strict penal colonies.

EU foreign policy chief Federica Mogherini urged Moscow 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.

Mogherini is expected to travel to Estonia on Monday for a pre-arranged visit, her spokeswoman told reporters. Baltic states Estonia, Latvia and Lithuania emerged from nearly five decades of Soviet occupation in the early 1990s and joined NATO and the European Union in 2004 in a bid to bolster their security as tensions simmered with Moscow.

Regional leaders 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.

In May, Russian security officials said they were holding a Lithuanian spy caught "red-handed" during an exchange of secret documents in Moscow. The announcement came just days after Lithuanian prosecutors said they had detained a Russian citizen suspected of spying. Brussels and Washington have slapped tough economic sanctions on Moscow over the Ukraine crisis, while Russia has responded by banning Western agricultural produce.

Independent Russian political analyst Masha Lipman told AFP that Kohver's lengthy sentence was a sign of deteriorating ties with Europe. "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." In a separate trial, Russian prosecutors on Wednesday asked for a 23-year term for Ukrainian film director Oleg Sentsov over alleged terror offences committed in his native Crimea region after it was seized by Russia last year.