Iran complained to the United Nations Security Council on Monday (March 31, 2025) about "reckless and belligerent" remarks by U.S. President Donald Trump, describing them as "a flagrant violation of international law" and the founding United Nations Charter. Mr. Trump threatened Iran on Sunday (March 30, 2025) with bombing and secondary tariffs if Tehran did not come to an agreement with Washington over its nuclear program. In a letter, seen by Reuters, Iran's U.N. Ambassador Amir Saeid Iravani wrote that Tehran "strongly warns against any military adventurism and will respond swiftly and decisively to any act of aggression or attack by the United States or its proxy, the Israeli regime, against its sovereignty, territorial integrity, or national interests."