To add details and quotes regarding new US strikes

By Steve Holland, Parisa Hafezi and Phil Stewart

WASHINGTON/DUBAI, July 12 (Reuters) - The U.S. military said it launched a new round of strikes on Iran after Revolutionary Guard forces attacked a Cyprus-flagged container ship passing through the Strait of Hormuz on Sunday.

The series of tit-for-tat attacks between the United States and Iran over the past few days has led US President Donald Trump to declare the end of the ceasefire agreement that was intended to halt the fighting that began with US and Israeli attacks on Iran on February 28, but Trump left the door open for continued negotiations.

Iran said it closed the vital Strait of Hormuz after firing warning shots at a ship sailing in an unauthorized channel. It warned that any retaliation for the incident would be met with a "harsh response."

The US Central Command stated that the M/V GFS, a container ship flying the Cypriot flag, sustained significant damage to its engine room and that a civilian crew member was missing.

The Strait of Hormuz is once again at the center of war and diplomacy.

The war destabilized the Gulf region, while Iran’s de facto blockade of the Strait of Hormuz caused energy prices to rise, exacerbating global inflation.

Rising prices, especially gasoline prices, are a politically sensitive issue for Trump ahead of the congressional elections scheduled for November.

Iran said several ships attempted to cross the waterway via an "unauthorized route" and ignored warnings to correct their course. The Revolutionary Guard declared that the strait—which before the war was a passage for a fifth of the world's oil and liquefied natural gas supplies—would remain closed until "American interference in this region ends."

Central Command said it began its strikes at 7:15 p.m. Eastern Time (2315 GMT) on Saturday, about an hour after the Iranian side issued a statement that included a warning that it would target "new enemy bases" in the Middle East if the United States responded to the container ship incident.

Central Command reported that Trump ordered the strikes. The White House has not yet responded to a request for comment.

Senior U.S. officials said the United States is demanding that Iran declare it will stop its attacks on ships in the Strait and that all passages will be open without tolls for the waterway.

Iranian Foreign Minister Abbas Araqchi accused the United States of violating the ceasefire agreement, writing on X on Friday, "Commitment can only be achieved reciprocally."

On Tuesday, Washington revoked the license that authorized the sale of Iranian crude oil after three Qatari and Saudi commercial tankers were fired upon last week, prompting the United States to target Iranian sites, while Iran responded by launching strikes on US military sites in Gulf countries.

Although Tehran has not claimed responsibility for the attacks on the ships, analysts believe it resorts to such moves to strengthen its negotiating position.

A senior Iranian source told Reuters that Iran, the United States, Qatar and Pakistan agreed to negotiate in a call that mediators tried to arrange on Saturday, while Araqchi was in Oman , which is trying to mediate an end to the war.

It is not yet clear whether these efforts have been successful.

Iran threatens to "avenge the blood of the martyred Supreme Leader"

Araghchi and Omani Foreign Minister Badr al-Busaidi met in the Sultanate to exchange views on appropriate mechanisms for the safe passage of ships through the Strait of Hormuz, according to a statement issued by the Iranian Foreign Minister.

The Omani News Agency later said that Omani and Iranian negotiators would continue talks "at both the technical and political levels."

CNN reported on Saturday that Oman had submitted a draft proposal regarding the Strait of Hormuz, which includes freedom of navigation through the southern passage in Omani territorial waters. CNN noted that the plan stipulates that ships transiting the northern passage through Iranian territorial waters would obtain prior approval from Iran, but without incurring fees.

Neither the White House nor the State Department has yet responded to requests for comment on the CNN report.

In a written statement, Iran’s new Supreme Leader Ayatollah Mojtaba Khamenei today threatened to avenge the killing of his father, former Supreme Leader Ayatollah Ali Khamenei, who was assassinated on February 28.

The statement was issued on the occasion of Khamenei’s funeral, which the new leader did not attend, and it stated that revenge would be taken no matter what happens to Iran.

The statement read, "We pledge to avenge the blood of the martyred Supreme Leader and all the martyrs."

Trump stated on Friday that he had ordered the US military to prepare to launch thousands of missiles at Iran if Tehran attempted to assassinate him.

The Wall Street Journal and other US media outlets reported days ago that Israel had passed intelligence information to Washington indicating that Iran had recently devised a plan to assassinate Trump.

Iran has not commented on the assassination plot allegations.

During the funeral service on Thursday, crowds of mourners packed the courtyard, some carrying signs that read "We will kill Trump."