US-Iran tensions escalate ahead of UN General Assembly with mutual threats of renewed conflict

A simultaneous exchange of threats between Washington and Tehran raised fears of a return to all-out hostilities in the Iran war ahead of the UN General Assembly in New York on Monday.

Iran's IRGC warned on Monday that the war with the US is not yet over and that it has prepared for a "long-term war" with weapons that have not yet been used, spokesman Hossein Mohebi said.

Mohebi said Iran had upgraded its weapons capabilities during and before the war, and described the unused systems as "strategic" and to be deployed if necessary.

Iran's Armed Forces General Staff, in a joint statement with the Khatam al-Anbiya Central Headquarters, claimed control of the Strait of Hormuz had passed to Iranian management and said its forces would not stand down.

The Khatam al-Anbiya headquarters said separately that it had obtained intelligence indicating the US, with support from unnamed regional countries, was preparing to resume strikes on Iran following a joint meeting held in an unspecified European country.

It said that in the event of a new US attack, "all of that country's bases and interests in the region, without any restrictions or consideration, will be subjected to continuous, effective and painful attacks." Iranian leaders have also warned that retaliatory action could target US naval forces in the Indian Ocean.

US President Donald Trump, who cut short his Camp David weekend and returned to the White House on Saturday evening without explanation, told Fox News he was weighing his options on Iran "if and when do I blow the entire nation up."

Trump has previously threatened to “wipe" Iran "off the face of this Earth," sparking considerable backlash at the time.

The US president is believed to be considering three paths: a large-scale military strike, a tightened economic blockade, or a diplomatic deal at the UN General Assembly. Trump is expected to meet the leaders of the six Gulf Cooperation Council states on the sidelines.

The US State Department issued fresh security warnings for US citizens across the Middle East, urging Americans in Iran to leave immediately and warning of possible flight cancellations and airspace closures.

Iran's Supreme National Security Council secretary Mohsen Rezaei said Tehran's preconditions for peace remain in place, including lifting the US blockade on Iranian oil ports, returning frozen assets and removing sanctions on oil exports.

Parliament speaker Mohammad Bagher Ghalibaf, presenting Iran's negotiating position in a parliamentary address on Sunday, said Tehran had no interest in a permanent war with Washington.

The escalating statements followed Houthi strikes on Saturday on targets in and around the Saudi capital Riyadh and on Aramco facilities in the Red Sea port city of Yanbu, using ballistic missiles, cruise missiles and drones.

Saudi Arabia said its air defences intercepted a ballistic missile fired at Riyadh at dawn; a fire was confirmed at a fuel depot near King Khalid International Airport, with large plumes of black smoke visible from the city, the first targeting of the Saudi capital since the resumption of the Yemen war.

The Houthis claimed to have caused "massive fires" at Aramco facilities, but the Saudi-led coalition said the attacks on Yanbu, Taif, Bisha and Farasan were thwarted.

Trump said in a Fox News interview that the US was "in constant contact with the Houthis" and that they had agreed not to go to war with Washington.

Trump rejected a request from Saudi Crown Prince Mohammed bin Salman for direct US military assistance against the Houthis last week, according to US media reports.