Norwegian Prime Minister Erna Solberg on Friday thanked Lithuania for its help in having Frode Berg, a Norwegian jailed in Russia for spying, back as part of a swap with Moscow.

Solberg confirmed that the Norwegian had been released and handed over to Norway's embassy in Vilnius on Friday.

"We are happy that Frode Berg will now come home to Norway as a free man," she said in a press release. "I want to thank the Lithuanian government for the cooperation and for the effort they have done in order to release Frode Berg."

Norwegian Foreign Minister Ine Eriksen Soreide said that "the time spent in prison has been a huge burden for Frode Berg and his family".

"We are happy that he can now reunite with his family. We have worked systematically to get Frode Berg home from the time he was arrested," she said.

Frode Berg / AP

The Lithuanian president's office said earlier on Friday that Berg, along with two Lithuanian citizens, Yevgeny Mataitis and Aristidas Tamošaitis, had been returned to Lithuania as part of the spy swap deal between Vilnius and Moscow.

In the exchange at a Lithuanian border crossing, Lithuania handed over two convicted Russian spies, Nikolai Filipchenko and Sergey Moiseyenko, to Russia.

Berg's Norwegian lawyer, Brynjulf Risnes, said his client had "recently crossed the border from Kaliningrad to Lithuania".

"I am in Lithuania waiting to meet him soon," he said.

The chief of the Norwegian military intelligence, Morten Haga Lunde, said through his spokesperson that he was "very happy that Frode Berg has been pardoned" after being convicted of espionage, according to NTB.

"The only thing we want to say now is that we are overjoyed and happy," Berg's daughter, Christina Berg, told the Norwegian news website VG.

Berg was sentenced to 14 years in prison in Russia earlier this year.

Tamošaitis was sentenced to 12 years in prison by a Moscow court in 2016. In the same year, a Kaliningrad court handed a 13-year jail sentence to Mataitis, a dual Lithuanian-Russian citizen.