DUBAI, United Arab Emirates (AP) — Iran said the Strait of Hormuz was closed once again after a warning shot fired by its military struck a vessel using an unauthorized route in the critical waterway, further jeopardizing the already tenuous ceasefire agreement with the United States.

U.S. Central Command said a short time later that its forces began a third round of strikes against Iran. There were explosions in Bandar Abbas and Sirik, two towns along the shores of the strait, Iran state media reported.

“The United States is imposing a heavy cost by continuing to degrade Iran’s ability to attack civilian mariners and commercial ships freely transiting the strait,” the American military said.

A Cyprus-flagged container ship was hit by Iran and suffered “significant engineroom damage” and a civilian crew member is missing, U.S. Central Command said.

Senior U.S. officials had previously said in Washington that negotiations to further cement last month’s deal to end the war will be unable to progress without the strait being secure — and even said they wanted Iran to offer public statements to that effect.

Instead, the Revolutionary Guards Corps said multiple vessels “disregarded our warnings and instructions to correct their course and proceed along the approved route.” One of them “was struck by a warning shot and brought to a stop.”

Iran said that the strait would remain closed “until further notice” and said it would consider targeting “additional enemy bases in the region” if it faced more attacks.

A little more than an hour later, the U.S. announced its own new round of strikes.

“Iran made a poor choice. Now they pay,” Defense Secretary Pete Hegseth posted on social media.

Attacks followed more diplomatic talks about the strait
The latest flurry of shots from both sides followed Iran and Oman’s foreign ministers meeting on Saturday to discuss the strait that lies between them, after days of Iranian attacks on ships and U.S. retaliation that dealt a blow to the interim deal to end the war.

Iran’s new supreme leader, still unseen since the war began, also vowed in his first statement since the funeral of his father, Ayatollah Ali Khamenei that Iranians would avenge his killing in the war’s opening strikes on Feb. 28.

Such revenge “is the will of our nation and must certainly be carried out,” Supreme Leader Mojtaba Khamenei said in a statement carried on state television, hours after President Donald Trump threatened more missile attacks.

Oman said it and Iran agreed to keep talking about the Strait of Hormuz “at the technical and political levels.”

Iran accuses Washington of violating ceasefire deal
Iranian Foreign Minister Abbas Araghchi said before the new round of strikes that he met with his counterpart in Oman to discuss “appropriate mechanisms for ensuring the safe passage of ships.”

The world for decades has considered the strait an international waterway. Iran has insisted that the strait now remain under its control and that it be allowed to charge ships moving through it, a stance it took after the war began. The U.S. urges mariners to transit on a southern route through Oman’s territorial waters.

About a fifth of all traded oil and natural gas passed through the strait before the war began. Iran’s grip on it during the war led to a global energy crisis, though oil prices have sharply dropped since wartime highs of $120 a barrel.

Iran’s top diplomat also accused the U.S. of violating the interim deal by ending waivers allowing Iran to sell crude oil on the open market in U.S. dollars. Washington ended them in response to the attacks on ships in the strait.

“Reality check: There can only be mutual compliance,” Araghchi wrote on social media.

Trump says he responded to threats to kill him
Trump said he’s personally been the target of an Iranian plot, and he said the U.S. military would automatically retaliate if he was killed.

He wrote on social media early Saturday that “1000 Missiles are Locked and Loaded and aimed at the Islamic Republic of Iran, with thousands of more to immediately follow, should the Iranian Government act on its threat.”

However, such retaliation would have to be ordered by Vice President JD Vance, who would become commander-in-chief if Trump were to be killed.

Trump said he was responding to threats “to assassinate, or attempt to assassinate” him. During Khamenei’s funeral, mourners held posters or banners calling for Trump to be killed along with Israeli Prime Minister Benjamin Netanyahu.

The U.S. president has declared the ceasefire over but said the U.S. would continue negotiations.

U.S. officials, speaking Friday on condition of anonymity about the current situation with Iran, said the resumption of strikes even before the latest round came as a result of what they described as a rogue faction of Iranian hard-liners who were trying to sabotage the ceasefire.

Iran has insisted its theocracy is unified under the new supreme leader.

After the U.S. wrapped up strikes on Thursday, more attacks reportedly hit Iran, raising questions about who else may be targeting the Islamic Republic.

Israel didn’t claim them, meaning the Gulf Arab states may have launched them, likely as a means to deter Iran from attacking them again. Iran on Thursday retaliated for U.S. strikes by targeting Bahrain, Jordan, Kuwait and Qatar.

The strikes in Iran over two days — and prior to the ones in the wake of the warning shot — killed at least 17 people and wounded 115 others, Iranian Health Ministry spokesperson Hossein Kermanpour said.