Iran responded to Washington's latest peace proposal on Sunday, after drones threatened several Gulf region targets and Tehran warned it would not hold back from retaliating against any new US strikes.
According to state broadcaster IRIB, Tehran's response, passed to Pakistani mediators, focuses on ending the war "on all fronts, especially Lebanon" -- where Israel has kept up its fight with Iran-backed Hezbollah -- as well as on "ensuring shipping security".
US President Donald Trump had said he was expecting Iran's reply by Friday, but as the wait dragged on, the ceasefire in the Gulf came under increasing strain, including from Sunday's drone strikes, one of which hit and damaged a freighter sailing towards a port in Qatar.
The United Arab Emirates accused Iran of being behind another attack that targeted its territory in what would be, if confirmed, only the second strike on a Gulf country since the start of the month-old truce.
"We will never bow down to the enemy, and if there is talk of dialogue or negotiation, it does not mean surrender or retreat," Iranian President Masoud Pezeshkian said on X Sunday.
Tehran's military chief Ali Abdollahi, meanwhile, met the country's supreme leader Mojtaba Khamenei and received "new directives and guidance for the continuation of operations to confront the enemy", according to Iranian state television.
- 'Restraint over' -
Qatar's defence ministry said a freighter arriving in the country's waters from Abu Dhabi was hit by a drone on Sunday off the port of Mesaieed.
The United Kingdom Maritime Trade Operations centre said the bulk carrier reported being struck by an unknown projectile.
"There was a small fire that has been extinguished, there are no casualties. There is no reported environmental impact," it said.
There was no immediate claim of responsibility, but Iran's Fars news agency reported that "the bulk carrier that was struck near the coast of Qatar was sailing under a US flag and belonged to the United States".
In a social media post on Sunday, the spokesman for the Iranian parliament's national security commission warned the United States: "Our restraint is over as of today."
"Any attack on our vessels will trigger a strong and decisive Iranian response against American ships and bases," Ebrahim Rezaei said.
Iran's Revolutionary Guards had threatened the day before to target US interests in the Middle East if its tankers came under fire -- as they did on Friday when a US fighter jet fired on and disabled two Iran-flagged vessels in the Gulf of Oman.
- Drone strikes -
The United Arab Emirates said that its territory had also come under attack, and called out Iran by name.
"UAE air defense systems successfully engaged two UAVs launched from Iran," the defense ministry said, in a social media post.
Iran's neighbor Kuwait also reported an attempted attack.
"At dawn today, the armed forces detected a number of hostile drones in Kuwaiti airspace, which were dealt with in accordance with established procedures," the military posted.
In Seoul, defense ministry spokesman Park Il told reporters that a South Korean cargo vessel had been hit on Monday and was damaged by fire before making its way to port in Dubai.
"On May 4, two unidentified aircraft struck the outer plate of the port-side ballast tank at the stern of the HMM Namu at roughly one-minute intervals, causing flames and smoke," he said.
Iran has choked off the Strait of Hormuz -- a vital route out of the Gulf for oil, gas and fertilizer, seeking to wield economic leverage over the United States and its allies.
The US Navy, meanwhile, is blockading Iran's ports, at times disabling or diverting ships heading to and from them.
Iran has set up a payment mechanism to extract tolls from shipping crossing the strait, but US officials have stressed it would be "unacceptable" for Tehran to control what had been an international waterway and the route of a fifth of the world's oil exports.
