US President Donald Trump on Wednesday warned Iran that it faced a "far worse" attack than last year's US strikes against its nuclear sites unless it quickly began talks.
His remarks on Truth Social, in which he repeated earlier warnings about an "armada" in the region, prompted Tehran to say that any US strike would see it "respond like never before".
The rhetoric comes after the USS Abraham Lincoln carrier strike group has arrived in the US Central Command's area of responsibility in the Middle East, meaning the Pentagon now has major firepower at its disposal to strike Iran.
"Hopefully Iran will quickly 'Come to the table' and negotiate a fair and equitable deal - no nuclear weapons - one that is good for all parties. Time is running out, it is truly of the essence!" Mr Trump said.
Mr Trump, who pulled out of a 2015 multination nuclear deal with Tehran during his first White House term, noted that his last warning to Iran was followed by a military strike, referring to Operation Midnight Hammer in June.
"The next attack will be far worse! Don’t make that happen again," Mr Trump wrote.
He told Axios on Tuesday: “We have a big armada next to Iran. Bigger than Venezuela,” referring to the naval vessels sent before special forces captured Venezuelan President Nicolas Maduro.
Iran's mission to the UN issued a statement on X saying that the last time the US "blundered" into wars it cost the country $7 trillion and more than 7,000 lives.
On Monday, a senior US official said Washington was “open for business”, in reference to talks with Iran. “If they want to contact us and they know what the terms are, then we're going to have the conversation,” the official said.
Iran's ambassador to the UN in Geneva, Ali Bahreini, said his country's Foreign Minister Abbas Araghchi and US special envoy Steve Witkoff were in contact. “They do not currently have a fixed channel of communication. It can hardly be called a negotiation,” Mr Bahreini said.
Mr Trump has repeatedly threatened to attack Iran and intervene if the regime continues its deadly repression of anti-government protests that swept the country.
Pro-Tehran militias around the Middle East have said they could retaliate if Iran is attacked again. “We do not take orders from Iran. But all resistance forces understand that a war on Iran is a war to dominate the entire region, and Iraq sits at the heart of these risks,” said a source close to Iraq's militant factions.
Referring to suggestions of a US attack on Iran's supreme leader Ayatollah Ali Khamenei, the source said: “Ali Khamenei is not merely an Iranian leader; he represents a symbol for the Islamic world and for a large segment of Iraqis and others. Any attempt to target him would ignite limitless anger against the enemies.”
A source in Iraq's Kataib Hezbollah group said fighters “will not stand idly by in the face of any escalation against Iraq”.
“All resistance forces in the world are concerned with confronting the terrorism practised against the peoples of the region in Palestine, Lebanon, Syria, Iraq, Iran and Yemen,” they said.
They said a warning by Yemen's Houthi rebels, who hinted at resuming attacks on Red Sea shipping, was “a message to those concerned, particularly about the capability and type of naval missiles, amid the growing military build-up across all the region’s seas”.
At least 5,800 people have been killed in the Iranian demonstrations, the US-based Human Rights Activists News Agency said. About 17,000 more deaths are under review as an internet shutdown continues, the agency added.
Iranian authorities have blamed the deaths on “foreign-backed” rioters, accusing the US and Israel of inciting violence and unrest.
Mr Trump said he held back from ordering military action against Tehran after being told protest killings were easing and plans for large-scale executions had been halted.
The USS Abraham Lincoln aircraft carrier is accompanied by three guided-missile destroyers. The carrier’s air wing uses F-35C fighter jets.
