Estonia and Russia have swapped two convicted spies after both men received presidential pardons, Estonian authorities say.
Officials on February 10 said Estonian businessman Raivo Susi was exchanged for Russian national Artyom Zinchenko at the Koidula border post in southeast Estonia.
"The Estonian state helps its citizens whenever it can," said Arnold Sinisalu, chief of the Baltic state's security police.
"Estonia deported to Russia the spy who had committed a crime here, and thus the Estonian businessman could return to the people close to him after being confined for a long time in Russia."
The Estonian man had been arrested at a Moscow airport in February 2016 over espionage charges related to his alleged actions from 2004-07. He was sentenced in 2017 to 12 years in a strict penal colony.
Susi, a co-owner of two companies involved in sales and repairs of aircraft, had been on his way to a Central Asian country when detained.
Zinchenko had been sentenced to five years in prison by a court in Tallinn last year, convicted of spying on behalf of Russia's GRU military intelligence.
Zinchenko, who had been living in Estonia since 2013, was found guilty of gathering and transmitting intelligence that compromised national security.
Authorities in the NATO-member Baltic states of Estonia, Latvia, and Lithuania -- all former Soviet republics -- have expressed concerns about Moscow’s intentions in the region, especially following its 2014 annexation of Ukraine’s Crimea region and its support for separatists in eastern Ukraine.
Other prisoner swaps have taken place between Estonia and Russia. In 2015, Russia freed Estonian officer Eston Kohver, who had been sentenced to 15 years in jail on espionage and other charges.
He had spent nearly 13 months in Russian prisons before his release.
In return, Tallinn freed Aleksei Dressen, a former Estonian security official serving a 16-year sentence in Estonia for spying for Moscow.
He had been detained in February 2012 and was found guilty of giving classified information to Russia for years following Estonia’s 1991 independence.
In May 2017, the Estonia Foreign Ministry announced it had expelled two Russian diplomats, without elaborating.
The Baltic News Service named the two diplomats as Dmitry Kazyonnov, Russia's consul-general in the city of Narva on the Estonian-Russian border, and consul Andrei Surgayev.
"This is another unfriendly and ungrounded move, which will not remain without a response," the Russian Foreign Ministry warned at the time.
With reporting by AFP, AP, and Baltic News Service