"I welcome today's release of wrongfully detained Allied citizens and Russian political prisoners. Close cooperation between NATO allies made this achievement possible," NATO chief Jens Stoltenberg said.

"It came at a cost, but it was weighted against the freedom and the lives of people unjustly imprisoned."

Jailed US journalist Evan Gershkovich and a Russian intelligence colonel jailed for a Berlin murder were among two dozen prisoners freed Thursday in the biggest East-West prisoner swap since the Cold War.

The prisoners were flown to Turkey's capital Ankara from Russia, the United States, Germany, Poland, Slovenia, Norway and Belarus under the complex deal.

In total, 10 Russians -- including two minors -- were exchanged for 16 Westerners and Russians imprisoned in Russia.

"Journalists and political opposition must be free to voice legitimate views without intimidation," Stotlenberg said.

"While the release of this group of political prisoners is a victory for diplomacy, too many others remain wrongly detained in Russia. I call for all those still unjustly imprisoned to be released."