Germany’s chancellor calls Putin ‘desperate.’

Chancellor Olaf Scholz of Germany said President Vladimir V. Putin of Russia was “desperate” when he directly challenged the West over its support for Ukraine with a veiled threat of using nuclear weapons.

In an hourlong interview with The New York Times on Wednesday, Mr. Scholz said Mr. Putin had gravely underestimated Ukraine’s ability to fight back and Western unity in supporting Kyiv, stressing that this unity was unshaken.

“It’s obvious that Putin does not know how to get out of this,” Mr. Scholz said. “It’s obvious that he will not win the war and Russia will not win the war.”

“He’s misguided, he underestimated the situation and he’s desperate,” Mr. Scholz added.

Mr. Putin’s announcement early on Wednesday that he was calling up 300,000 reservists and moving ahead with annexing parts of eastern Ukraine was an attempt to demonstrate determination after humiliating defeats on the battlefield that have undermined his leadership at home and abroad. By raising the specter of a tactical nuclear strike he also escalated Russia’s tense showdown with Western nations that have bolstered Ukraine with weapons, money and intelligence that have helped Ukraine reclaim swaths of territory in the northeast.

“If the territorial integrity of our country is threatened, we will certainly use all the means at our disposal to protect Russia and our people,” Mr. Putin said. “This is not a bluff.”

Mr. Scholz described the situation as “dangerous” and said his priority remained preventing direct confrontation between Russia and NATO.

“We always have to be very serious about the use of nuclear weapons and Russia is a nuclear power, as we all know,” Mr. Scholz said. “No one that is a responsible leader forgets.”

“But it doesn’t change what we are doing,” he added. “We are supporting Ukraine. We are doing it in a way that this is not escalating where it is becoming a war between Russia and NATO because this would be a catastrophe.”

Asked how Western countries would respond if Mr. Putin did deploy tactical nuclear weapons, the chancellor declined to specify. “We are saying, ‘Don’t even think about it and don’t do it,’” Mr. Scholz said. “That’s what we can say to it.”