U.S. President Donald Trump unleashed a sharp warning to Russia on Sunday, vowing to slap secondary tariffs of 25% to 50% on Russian oil buyers if Moscow derails his push to end the Ukraine war.

In a fiery NBC News phone interview, Trump said he’s “pissed off” at Vladimir Putin’s recent jabs at Ukrainian President Volodymyr Zelenskyy’s legitimacy, signaling growing frustration with Russia’s role in the three-year conflict that erupted in February 2022.

“If Russia and I can’t stop the bloodshed in Ukraine—and if I think it’s Russia’s fault—I’m hitting their oil with tariffs,” Trump declared, pegging the move within a month if no deal emerges. “Buy from Moscow, and you’re out of business with the U.S.”

The threat, aired early Sunday from his Palm Beach estate, follows Putin’s Friday call for a transitional Ukrainian government—words Trump slammed as veering “in the wrong direction” for peace.

Trump, who’s banked on brokering a swift ceasefire since taking office in January, plans to confront Putin this week, building on two known calls since November—though the Kremlin hints at more.

The U.S. State Department doubled down, stating Trump won’t let Russia off the hook: “He’s open to a deal, but if they don’t bite, options get ugly for Moscow.” With Russia’s economy already battered, Trump’s tariff gambit aims to squeeze oil-reliant nations like China and India, who’ve ramped up purchases since Western sanctions bit.

The shift jars with Trump’s earlier chummy tone toward Putin, whom he’s called a friend despite past tensions—like the 2020 Soleimani strike. As Ukraine’s war grinds on, Trump’s patience is thinning—peace, he insists, or Putin pays.