President Vladimir V. Putin of Russia accelerated his war effort in Ukraine on Wednesday, announcing a new mobilization campaign that would call up roughly 300,000 additional soldiers while also directly challenging the West’s support for Ukraine with a veiled threat of using nuclear weapons.
In a rare videotaped address to the nation, Mr. Putin stopped short of declaring a full, national draft but instead called for a “partial mobilization” of people with military experience. Though Moscow’s troops have recently suffered humiliating losses on the battlefield, he said that Russia’s goals in Ukraine had not changed and that the move was “necessary and urgent” because the West had “crossed all lines” by providing sophisticated weapons to Ukraine.
The speech was an apparent attempt to reassert his authority over an increasingly chaotic war that has undermined his leadership both at home and on the global stage. It also escalated the tense showdown with Western nations that have bolstered Ukraine with weapons, money and intelligence that have contributed to Ukraine’s recent successes in reclaiming swaths of territory in the northeast.
Mr. Putin accused the United States and Europe of engaging in “nuclear blackmail” against his country and warned that Russia had “lots of weapons” of its own.
“To those who allow themselves such statements about Russia, I want to remind you that our country also has various means of destruction, and some components are more modern than those of the NATO countries,” he said.
He reaffirmed his support for referendums hastily announced on Tuesday that have set the stage for Mr. Putin to declare that occupied Ukrainian territory has become part of Russia. That annexation could potentially come as soon as next week.
Pro-Kremlin analysts and officials have said that at that point, any further Ukrainian military action on those territories could be considered an attack on Russia itself; Mr. Putin did not spell that out, but warned that he was ready to use all of the weapons in Russia’s arsenal to protect what the Kremlin considered Russian territory.
“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,” he said. “This is not a bluff.”
In announcing a call-up of soldiers, Mr. Putin was also responding to those in Russia who support the war but have criticized the Kremlin for not devoting the resources and personnel necessary to wage an all-out fight. Mr. Putin had previously avoided conscription in an effort to keep the war’s hardships as distant as possible from ordinary Russians, but the recent battlefield setbacks, and the drumbeat from pro-war nationalists for a more robust effort, apparently changed the calculation.
In a subsequent speech, Russia’s defense minister, Sergei Shoigu, put the number of new call-ups at 300,000 people, all of them with some military experience. He said that students would not be called up to fight and that conscripts would not be sent to the “special operation zone,” the way the Kremlin refers to the war, though observers were skeptical of that claim.
The number of Russian troops, including Russia-aligned separatists, members of private security companies and volunteers, does not currently exceed 200,000, according to estimates by military analysts and experts. If the partial mobilization is successful, the new recruits would more than double that amount, which would make it easier for Russia to defend hundreds of miles of front lines in Ukraine. However, observers say, most high ranking personnel have already ben deployed, and those called up will need further training and weapons.
Ivan Nechepurenko and Alina Lobzina contributed reporting.