Iran's chief negotiator, Mohammad Bagher Ghalibaf, accused the United States of major violations of the memorandum of understanding between the two countries in a post on X on July 8.

His comments come as the US military continues to strike Iran's southern areas of Bandar Abbas and Sirik, according to Iranian reports late on July 8.

The statement points to the unravelling of an accord signed last month to extend a ceasefire, coming as Tehran and Washington traded strikes and the US revoked a waiver allowing sales of Iranian oil.

Ghalibaf listed what he described as US breaches, including violating Iranian adjustments in the Strait of Hormuz, persistent threats of further strikes, the reinstatement of oil sanctions, and attacks on southern Iran.

The Iranian official also cited what he called continued Israeli aggression against Lebanon following more than 24 hours of exchanges between IRGC forces and US military across the region.

"The era of bullying and extortion is over. It leads nowhere. We don't fold," Ghalibaf wrote.

The comments followed US Central Command's announcement of strikes on Iran in response to attacks on three commercial ships in the Strait of Hormuz, and the US Treasury's cancellation of a licence that had allowed Iran to sell crude.

US President Donald Trump said the ceasefire was over, telling reporters at the Nato summit in Ankara that as far as he was concerned it had ended.