Russia must stop 'irresponsible' nuclear rhetoric, says NATO chief

Jens Stoltenberg warned Russia against using nuclear, biological or chemical weapons in Ukraine, while stressing NATO's readiness to 'protect and defend allies against any threat any time'

NATO will likely decide on Thursday to ramp up military forces on its eastern flank, the head of the alliance said, while also warning Russia against using nuclear weapons after its Feb. 24 invasion of Ukraine.

NATO has sharply increased its presence at the eastern border of the alliance, with some 40,000 troops spread from the Baltic to the Black Sea, and is seeking to deploy four new combat units in Bulgaria, Hungary, Romania, Slovakia.

"I expect leaders will agree to strengthen NATO's posture in all domains, with major increases in the eastern part of the alliance. On land, in the air and at sea," NATO chief Jens Stoltenberg told a news conference ahead of a NATO summit in Brussels on Thursday.

Putin sent troops into Ukraine in what he calls a "special military operation" to demilitarise and "denazify" Ukraine.

Ukraine and the West say Putin launched an unprovoked war of aggression.

The additional multinational battlegroups come on top of four existing combat units, with a total of some 5,000 troops, deployed by NATO to the three Baltic states and Poland after Russia's annexation of Crimea in 2014.

Stoltenberg said the Ukraine crisis had shown that NATO must reset its deterrence and defence posture for the longer term, an issue NATO leaders are expected to discuss at their next regular summit at the end of June in Madrid.

"There is a new sense of urgency because we cannot take peace for granted," he told reporters.

NATO leaders are also set to agree additional aid for Kyiv, according to Stoltenberg, including equipment to help Ukraine protect against chemical, biological, radiological and nuclear threats.

He warned Russia against using nuclear, biological or chemical weapons in Ukraine, while stressing NATO's readiness to "protect and defend allies against any threat any time".

"Russia should stop this dangerous irresponsible nuclear rhetoric... Russia must understand that it can never win a nuclear war," he said, adding that any use of biological or chemical weapons would have "far-reaching consequences".

Stoltenberg also called on China to condemn Russia's war in Ukraine and to not provide "material support" for Moscow.

China has not condemned Russia's invasion, though it has expressed concern about the war. Chinese Vice Foreign Minister Le Yucheng said on Saturday that Western sanctions against Russia were getting "more and more outrageous".

"For NATO, it is of particular concern that China now, for the first time, has questioned some of the key principles for security, including the right for every nation in Europe to choose his own path," Stoltenburg said.

In a show of Western unity against the war in Ukraine, Brussels will also host a G7 and an EU summit on Thursday.