NATO Chief: Putin's Nuclear Warning Irresponsible and Dangerous

Russian President Vladimir Putin's decision to put his nuclear weapons on alert is "irresponsible," NATO said on Sunday.

"This is dangerous rhetoric. This is a behavior which is irresponsible," Jens Stoltenberg, secretary-general of NATO, spoke to CNN amid increasing tensions over Russia's invasion of Ukraine.

"And, of course, if you combine this rhetoric with what they're doing on the ground in Ukraine, waging war against the independent sovereign nation, conducting a full-fledged invasion of Ukraine, this adds to the seriousness of the situation," he said.