Putin said he thought the move would be a mistake, but did not repeat earlier threats that any such move would trigger countermeasures from Moscow, the Finnish leader said in an interview with CNN on Sunday.
"Altogether, the discussion was very, would I say, calm and cool," Niinisto said. "The surprise was that he took it so calmly."
However, he added: "You have to keep in mind that what he said doesn't mean that you shouldn't be all the time quite, well, aware and follow up what really is happening. But so far, it seems that there's no immediate problems coming." The Finnish president expressed readiness to hold talks with his Turkish counterpart Tayyip Erdogan after Ankara raised objections to the Nordic countries joining NATO.