President Trump dug in on his criticism of Russian President Vladimir Putin on Tuesday, warning that Russia’s leader is “playing with fire.”

“What Vladimir Putin doesn’t realize is that if it weren’t for me, lots of really bad things would have already happened to Russia, and I mean REALLY BAD,” Trump posted on Truth Social. “He’s playing with fire!”

Trump bashed Putin on Sunday for his attacks on Ukraine, where the U.S. is attempting to broker a ceasefire.

Russian drones and missiles bombarded more than two dozen cities across Ukraine over the weekend. Trump in a social media post Sunday night claimed Putin is going “absolutely” crazy and said if he did not stop the strikes on Ukraine, it would lead to the downfall of his country.

The Kremlin responded to his criticism Monday, citing “emotional overload” at this “very important moment.”

Russia invaded Ukraine in February 2022 after amassing troops near the border. Trump has pushed for an end to the conflict, alternately expressing frustration with Putin and Ukrainian President Volodymyr Zelensky over the inability to end the conflict.

Some U.S. lawmakers, including Republicans, have urged Trump to press forward with additional sanctions and take a firmer stance against Putin and Russia in response to their lack of engagement on ceasefire talks. Critics have argued Putin is dragging his feet on peace efforts as he carries out attacks in Ukraine while stringing Trump along.