Iran Warns of ‘Harsh’ Response After Trump Threatens Action Over Missile, Nuclear Revival

Iranian President Masoud Pezeshkian on Tuesday (December 30, 2025) issued a sharp warning to the United States, saying Tehran would respond with a “harsh” and “regrettable” reaction to any act of aggression, following renewed threats from US President Donald Trump over Iran’s alleged efforts to revive its ballistic missile and nuclear programmes.

What did the Iranian President say about the US?

Without directly naming Trump, Pezeshkian said the Islamic Republic would not tolerate coercion or military pressure.

“The response of the Islamic Republic of Iran to any oppressive aggression will be harsh and regrettable,” he wrote in a post on X, signalling Tehran’s readiness to retaliate if confronted militarily.

Why did the Iranian President react this way?

The remarks came after Trump warned that Washington was closely monitoring Iran’s activities and would not hesitate to act if evidence emerged that Tehran was rebuilding its missile capabilities or advancing its nuclear programme.

Speaking at a press conference alongside Israeli Prime Minister Benjamin Netanyahu, Trump said any such move by Iran would invite decisive consequences. “If they are [building up again], we’re going to have to knock them down,” he said.

What threat did Trump issue to Iran?

Trump further underlined US support for Israel, stating that Washington would respond “immediately” if Iran pressed ahead with missile development or nuclear enrichment. “The nuclear? Yes, absolutely,” he said when asked whether the US would intervene.

Tensions between Washington and Tehran remain high following US military strikes in July on Iran’s nuclear facilities at Fordo, Isfahan and Natanz, which Trump described as a major success. Media reports said B-2 stealth bombers were instrumental in the operation, which aimed to cripple Iran’s nuclear infrastructure.

Why is this exchange of warnings significant?

The latest exchange also comes amid fragile regional dynamics. A US-mediated ceasefire between Israel and Hamas has largely held but has lost momentum, with accusations of violations from both sides and disagreements among the US, Israel, and Arab states over the next steps.

Trump met Netanyahu in Florida to discuss the Gaza conflict and the future of the ceasefire, even as Iran-US rhetoric once again raised fears of a wider regional escalation.