NATO secretary general Jens Stoltenberg said on Sunday that Putin's nuclear rhetoric is dangerous and reckless.
Speaking to NBC, Stoltenberg warned Russia of severe consequences in case of a possible use of nuclear weapons.
Making remarks on the Ukrainian territories that are annexed by Russia, he said that "the best way to respond to it is to continue supporting Ukraine."
Speaking about Ukraine's application for accelerated membership in NATO, Stoltenberg said it has to be agreed upon by all NATO allies.
NATO supports the investigation into the apparent sabotage of Russia's Nord Stream pipelines that run from Russia to Europe under the Baltic Sea, the NATO chief said.
He also said that "Any deliberate attack on NATO critical infrastructure will be met with a firm and united response."
