Iran rejected talks with the United States on Sunday, as President Donald Trump threatened to bomb the country as “never seen before” to prevent the terror-supporting state from becoming a nuclear-armed power.

Trump said in early March that he had sent a letter to the so-called Islamic Republic’s “Supreme Leader,” Ayatollah Ali Khamenei, proposing direct talks over Iran’s nuclear program in order to prevent a military confrontation.

After Iranian-backed Houthi rebels in Yemen continued to launch missiles at Israel, as well as the U.S. Navy and international shipping in the Red Sea, Trump said that Iran would be held directly accountable for the actions of its proxy.

The Associated Press reported that Iran had rejected Trump’s offer — and that Trump threatened bombing in response:

Iran’s president said Sunday that the Islamic Republic rejected direct negotiations with the United States over its rapidly advancing nuclear program, offering Tehran’s first response to a letter President Donald Trump sent to the country’s supreme leader.

President Masoud Pezeshkian said Iran’s response, delivered via the sultanate of Oman, left open the possibility of indirect negotiations with Washington.

…

The White House, the State Department and other officials offered no immediate reaction to the announcement. However, Trump said before Pezeshkian’s comments he was considering military action and secondary tariffs if Iran does not agree to a nuclear deal.

“If they don’t make a deal, there will be bombing and it will be bombing the likes of which they have never seen before,” Trump said in a comment aired Sunday by NBC News.

Iran has no effective air defenses, after they were largely destroyed by Israel in retaliation for ballistic missile attacks last year. Iran is possibly gambling that Trump would not dare follow through on his recent threats of military action.