President Donald Trump on Sunday condemned the decision by Russian President Vladimir Putin to unleash one of the largest offensives in Russia’s war against Ukraine and said he was considering imposing more sanctions on Russia in response.

“I don’t know what the hell happened to Putin,’’ Trump told reporters Sunday afternoon, just before boarding Air Force One for a short trip from his golf club in New Jersey to Washington. Hours later, he posted about the Russian leader, saying, “He has gone absolutely CRAZY.”

Trump said he was “not happy” with Putin’s escalating his attacks, especially as the two countries negotiate a ceasefire deal to bring the three-year war to an end.

“He’s killing a lot of people, and I don’t know what the hell happened to Putin,” Trump said. “I’ve known him a long time. Always gotten along with him. But he’s sending rockets into cities and killing people, and I don’t like it at all.”

Trump, who has largely sided with Russia in the war, said he was “surprised” by the recent escalation, continuing to downplay the fact that it was Russia that initiated the war with an unprovoked invasion.

Trump also wrote that Putin’s continued incursion could have dire consequences.

“I’ve always said that he wants ALL of Ukraine, not just a piece of it, and maybe that’s proving to be right, but if he does, it will lead to the downfall of Russia!” he wrote.

Trump’s remarks came after Russia carried out one of its largest drone and missile barrages of the war on Ukraine, killing at least 12 people and injuring dozens across the country.

Asked whether he was considering levying additional sanctions against Russia, which he has threatened several times, Trump responded: “Absolutely. He’s killing a lot of people.”

Moscow avoided a harsh reaction to Trump’s post. Kremlin spokesperson Dmitry Peskov, expressed gratitude to the U.S. president for pressing negotiations between Russia and Ukraine, calling the start of talks in Istanbul earlier this month “a very important achievement.”

Peskov said Putin was taking necessary measures to protect Russia.

In his rebuke of Putin, Trump also had harsh words for President Volodymyr Zelenskyy of Ukraine. Earlier Sunday, Zelenskyy had lamented what he called the “silence of America” and other countries in the face of Russia’s renewed attacks and said they were only encouraging Putin.