Tehran said on Sunday it carried out a third day of retaliatory strikes against US attacks on Iranian territory, as both accused the other of violating their fragile ceasefire, straining negotiations meant to end the Middle East war.

The exchanges underscored the fragility of a Pakistan-brokered peace process aimed at ending a war launched by the United States and Israel in February, which disrupted shipping through the Strait of Hormuz and rattled global energy markets.

Iran’s Islamic Revolutionary Guard Corps (IRGC) said on Sunday they were taking measures to control traffic in the vital Strait of Hormuz and that violating vessels would be dealt with more firmly than before.

The only authorised passage by Tehran passes through a corridor running along Iran’s coast.

The Guards said they had also carried out retaliatory strikes in Kuwait and Bahrain.

In a statement, they said the strikes “destroyed eight important US military facilities at the Ali al-Salem base in Kuwait and at the Fifth Fleet naval base in Port Salman in Bahrain”.

“Any enemy aggression, whatever the pretext, even against insignificant targets… will have a crushing response,” the IRGC said.

Air raid sirens rang out twice in Bahrain on Sunday, according to the Gulf nation’s interior ministry.

The Guards said in a statement that the US strikes had violated the ceasefire and “will result in the complete halt of all diplomatic processes”, according to state-run Press TV. The IRGC navy command said American bases in the region “will experience hell in the coming days”.

A US official, confirming the attacks on US facilities, told Reuters there were no reported US casualties or major damage to US sites in the Middle East but that the situation was still unfolding.

Hours later, alarms sounded for a second time in Bahrain, with the authorities saying an Iranian attack damaged a residential building in Muharraq province, with no casualties reported.

Bahrain urged the United Nations Security Council to hold an urgent session to hold Iran accountable. The Kuwaiti army said it had intercepted two ballistic missiles with no damage or casualties.

A memorandum of understanding (MoU) was reached between the US and Iran on June 18 under Pakistan’s mediation, aimed at putting a lasting end to the war.

The text signed by the United States and Iran said both countries, and their respective allies, were “not to initiate any war or any military operation against each other and to refrain from the threat or use of force against each other”.

Iran would ‘no longer exist’

US President Donald Trump early on Sunday said that Iran would “no longer exist” if the United States is “forced” to resume the war.

The threat came after US forces said they struck “multiple” Iranian targets Saturday in another tit-for-tat response to attacks on shipping in the Strait of Hormuz.

“United States aircraft just struck Iranian missile and drone storage locations, and coastal radar sites, for violating the Cease Fire Agreement, AGAIN!” Trump wrote on Truth Social.

“There may come a point when we are no longer able to be reasonable, and will be forced to militarily complete the job that we very successfully started. If that happens, the Islamic Republic of Iran will no longer exist!” Trump wrote.

Shipping lanes under fire

US Central Command said Saturday’s strikes were in response to an Iranian drone attack on the Panama-flagged oil tanker “Kiku”, which was carrying some two million barrels of crude.

The US military said its operation targeted “surveillance infrastructure, communication systems, air defence sites, drone storage facilities, and minelayer capabilities”.

Iranian state broadcaster IRIB said explosions were heard in Sirik in southern Iran, without providing details.

The Guards said, “America’s blind shots at Sirik will not resolve our dominance over the Strait of Hormuz. But our shots at violators will remind the rest of the vessels of the clear passage route.”

Washington had carried out similar strikes on Friday, saying they were a response to an earlier Iranian attack on another vessel, the “Ever Lovely”.

Israel, meanwhile, launched strikes in Lebanon as Hezbollah’s leader Naim Qassem rejected a deal to end that conflict, which has also threatened to derail the wider US-Iran peace effort.

Iran called “these brutal attacks… a blatant violation” of the interim truce deal.

Iran has warned vessels not to enter or leave the Gulf through the strait without permission, but ships have continued to move, some using a route not authorised by Tehran.

In the Islamabad MoU, Iran had previously agreed “safe passage of commercial vessels with no charge, for 60 days only, from the Persian Gulf to the Sea of Oman, and vice versa” in the strait.

H.A. Hellyer, of London think tank the Royal United Services Institute, said, “Iran is likely to continue calibrated, low-level coercive activity in and around the Strait of Hormuz… to create persistent pressure on international shipping without triggering a wider conflict.”

He said November’s US midterm elections for Congress give Washington “incentives for a quicker agreement” while, for Iran, “a drawn-out negotiation accompanied by controlled pressure in the strait can work to its advantage”.

Lebanon threats

Lebanon, from where Hezbollah launched rockets at Israel in support of Iran, has been invaded and heavily bombarded by Israel, undermining the US-Iran ceasefire.

Israel and Lebanon signed an agreement on Friday, supported by the US, aimed at securing long-term peace between the two countries.

Hezbollah’s chief Qassem rejected the deal a day later, calling it “humiliating, shameful and a surrender of sovereignty”. He instead called for the full implementation of Washington’s deal with Tehran, which includes an end to the fighting in Lebanon.

Hezbollah has repeatedly called for a full Israeli withdrawal from southern Lebanon, but the Washington deal does not appear to provide for that.

Israeli Prime Minister Benjamin Netanyahu has insisted Israeli troops will remain in the so-called security zone they occupy in southern Lebanon, with civilians prevented from returning until Hezbollah is disarmed.

The Israeli premier called the deal historic on Saturday and “a blow to Iran and Hezbollah”. But Netanyahu’s far-right security minister Itamar Ben Gvir denounced it as “a big mistake” and insisted that only Israeli forces were capable of disarming Hezbollah.