Thors was disappointed that a much-needed dialogue between Russia and other OSCE members couldn't happen.
In response to the travel ban by Finland that Moscow considered openly unfriendly, the Russian delegation decided to refrain from participating in the summer session. Furthermore, the Russian State Duma is considering possible economic sanctions against Finland, according to Alexei Pushkov, head of the foreign affairs committee of the lower house of Russia's parliament.
Russia's participation at the OSCE assembly meeting would have been welcomed by everyone, Thors said.
"It's very regretful, especially considering that one of the main ideas of the organization is to always maintain a dialogue," Thors told Yle.
An OSCE Parliamentary Assembly meeting in Helsinki is taking place on July 5-9.
The delegations of Cyprus, Armenia, France, the Netherlands, Germany and Belarus, as well as a number of other delegations, expressed regret that Russian parliamentarians were not able to participate in the session, stressing that it diminished the credibility of the OSCE as an international organization.