MOSCOW, March 6 (Reuters) - Russia said on Friday it would respond if Finland placed nuclear weapons on its territory, saying such a move would make the Nordic country more vulnerable. The Kremlin reacted sharply after NATO member Finland said on Thursday it was planning to lift a longstanding ban on hosting such weapons, in a move that could open the door to placing them there during times of war. "This is a statement that leads to an escalation of tensions on the European continent," Kremlin spokesman Dmitry Peskov told reporters. "This statement adds to Finland's vulnerability, a vulnerability provoked...