NATO discusses Russia missile treaty 'violations': Mattis
Washington claims that Russia has broken with the Intermediate Nuclear Forces Treaty, signed during the Cold War, that prohibits the deployment of short- and intermediate-range missiles.
"We have a firm belief now over several years that the Russians have violated the INF," Mattis said.
"Our effort is to bring Russia back into compliance, it is not to walk away from the treaty."
President Ronald Reagan and the then-leader of the Soviet Union Mikhail Gorbachev signed the INF into effect in 1987.
Moscow has repeatedly denied claims that its recent deployment of a land-based missile system breaks the treaty.
Mattis said several NATO nations had their own evidence that Russia was not in compliance.
"The discussion included a consideration of the Russian Federation's violations of the intermediate nuclear forces treaty, and our collective efforts to bring Russia back into compliance," Mattis said at a NATO summit in Brussels.
"This is absolutely necessary to sustain confidence in arms control agreements and we are doing so in a substantial, transparent, and verifiable fashion," he added, without giving details.
Moscow has accused America of its own violations of the treaty, saying the US Patriot missile system in Poland and Romania could be tailored if necessary to shoot missiles at Russia.
