Jasem Mohamed Albudaiwi, the secretary-general of the Gulf Co-operation Council, accused Iran of committing “war crimes” with attacks on civilian infrastructure including water desalination plants.
Tehran characterised the strikes as revenge for the week-long American campaign that has begun to target non-military sites including roads, bridges and – according to the Islamic Republic – one of its own drinking water facilities.
On Saturday night, Mr Khamenei accused Washington of “repeated violations” of the preliminary memorandum of understanding (MoU) the two nations signed a month ago.
A written statement attributed to the supreme leader said that the US attacks “once again proved to everyone how worthless and unreliable the signature of the US president is”. Mr Khamenei has not been seen in public since he was wounded in the Feb 28 strike that killed his father.
He warned that Tehran had “unforgettable lessons in store” for the “American enemy”.
Earlier, Kazem Bharibabadi, the Iranian deputy foreign minister, announced that the country had entirely suspended its participation in the MoU, which envisioned a 60-day truce leading to a deal that would limit the regime’s nuclear programme in exchange for sanctions relief.
Washington is in the process of deploying dozens of refuelling aircraft to bases in Israel, in what could be the prelude to an expansion of its military campaign.
On Saturday, Kuwait said Iran had struck a water-desalination plant for the second time in two days. The Gulf state relies on such facilities for 90 per cent of its drinking water.