RAMSTEIN AIR BASE, Germany — Defense Secretary Lloyd Austin told a gathering of military leaders from 40 NATO and non-NATO countries that Russian President Vladimir Putin “never imagined that the world would rally behind Ukraine so swiftly and surely” — as the United States pledged military aid, Poland announced it would send tanks, and Germany planned to send armored antiaircraft vehicles.

In separate remarks to the group, Gen. Mark Milley, chairman of the Joint Chiefs of Staff, offered a stark picture of the next phase of the war, as Russia attempts to take full control of southeastern and southern Ukraine. “Time is not on Ukraine’s side,” Milley said in closed-door comments provided to reporters traveling with him. “The outcome of this battle, right here, today, is dependent on the people in this room.”

World leaders are seeking to pressure Putin to stop the war now grinding into its third month. U.N. Secretary General António Guterres, who is in Moscow to meet with Putin and his foreign minister Sergei Lavrov, called for a cease-fire on Tuesday and said everything must be done “to end the war as soon as possible.” Lavrov, meanwhile, set off alarm bells when he told state television that the risk of the conflict escalating into nuclear war “is serious, it is real” — but added that Moscow’s position is that nuclear war is unacceptable. Lavrov accused NATO of fighting a proxy war by donating weapons to Kyiv and said weapons flowing from allies into Ukraine will be considered “a legitimate target” for Russia’s military.

Here’s what else to know

  • Experts from the U.N. nuclear watchdog will visit the Chernobyl nuclear power plant site on Tuesday, in the first full international inspection since Russian forces occupied the area.
  • The U.N. refugee agency said up that to 8.3 million people could flee Ukraine into neighboring countries — nearly double its initial projections from the first weeks of the war.
  • Moldova’s president convened a meeting of the country’s security council Tuesday after multiple explosions were reported in the breakaway republic of Transnistria, which is backed by Moscow and borders Ukraine. No one has claimed responsibility. A Russian military commander suggested last week that Moscow aims to establish a corridor through southern Ukraine to Transnistria, but it’s unclear whether this reflects the official Kremlin line.
  • The Washington Post has lifted its paywall for readers in Russia and Ukraine. Telegram users can subscribe to our channel for updates.