Estonian security officer Eston Kohver, imprisoned by Moscow on espionage charges, is back home after being exchanged for jailed Russian spy Aleksei Dressen.

Kohver, an officer with the country's Internal Security Service, said at a press conference in Tartu on September 26 that he was "happy to be home again."

He said he wanted to "thank everyone who helped my family manage without me and everyone who helped me during my imprisonment and helped me finally return to Estonia."

Kohver, who spent almost 13 months in Russian prisons, was reunited with his family upon his return to Estonia.

The prisoners were swapped in southeastern Estonia at the border with Russia.

Estonian Interior Minister said Kohver's release was made after "lengthy negotiations."

Estonian President Toomas Hendrik Ilves called Kohver a "tough and loyal" officer.

Kohver's release was hailed by Estonian Foreign Minister Marina Kaljurand as "good news for Estonia and the whole of Europe" as she thanked countries for pressuring Moscow to agree to the exchange.

The U.S. Embassy in Tallinn wrote a tweet on September 26 saying "we welcome the Estonian-Russian agreement to swap Eston Kohver back to Estonia."

Two border checkpoints were closed during the exchange, which took place on a bridge over the Piusa River that divides Russia’s western Pskov region and Estonia’s Polva county, according to a statement by Russia's Federal Security Service (FSB).

The exchange comes as Russian President Vladimir Putin is due to address the UN General Assembly on September 28.

WATCH: Do You Know Eston Kohver? (in Russian)

Kohver’s defense lawyer, Mark Feigin, said that the swap was “organized on the political level” and was timed to improve Putin’s image before his appearance at the UN.

In a tweet, Feigin wrote: "It's all happening ahead of Putin's visit to the UN...There are no other reasons."

Kohver was sentenced to 15 years in jail on August 19 at a closed-door trial after being found guilty of espionage and illegally crossing the Russian border.

Estonia vehemently denied the charges, saying Kohver was abducted in Estonia a year ago and dragged into Russia.

On September 10, EU lawmakers urged Russia to release Kohver, along with Ukrainian filmmaker Oleg Sentsov and civil activist Oleksandr Kolchenko, calling their detentions a "blatant violation of the territorial integrity of Ukraine and Estonia through the illegal kidnapping of citizens of both countries."

Dressen, a longtime Estonian security official, was detained in February 2012 by police on suspicion of spying for Russia.

He was found guilty of giving classified information to Russia for years following Estonia’s 1991 independence and was sentenced to 16 years for treason.

His wife, Viktoria Dressen, who Estonia accused of forwarding information to Russia's FSB, was given a suspended sentence of six years in jail.

Estonian Prime Minister Taavi Roivas, who turned 36 on September 26, said the news from the Interior Ministry was the best birthday present he could receive.

With reporting by Interfax, RIA Novosti, Estonian Public Broadcasting, and AFP