"Putin has seen the West weakness in Ukraine, and he wants to exploit that," he told a press conference at BNS via videoconferencing.

"I fear very much that he will try something in the Baltic states because he can see that if he destroys NATO's credibility in the Baltic states, then he destroys NATO, and this is a very tempting target for him," Lucas said.

Lucas spoke during the press conference held by human rights activists to announce a list of political prisoners in Russia.