The Iran-blockaded Strait of Hormuz saw a series of new attacks Thursday, a world away from Beijing, where Donald Trump discussed the Iran war with China's President Xi Jinping.
The latest attacks brought a grim reminder of the costs of a prolonged stalemate, with peace talks virtually stalled.
After Trump and Xi met, a White House official said the leaders had agreed that the strait should be open and that Iran should never obtain nuclear weapons. China is close to Iran and the main buyer of its oil.
In an interview with CNBC in Beijing, U.S. Treasury Secretary Scott Bessent said he believed China would "do what they can" to help open the strait, which he said was "very much in their interest."
But diplomacy to end the war has been on hold since last week when Iran and the United States each rejected the other's latest proposals, sticking to initial demands that each considers to be "red lines."
Iran has largely shut the Strait of Hormuz to ships apart from its own since the United States and Israel launched their bombing campaign two-and-a-half months ago, causing the biggest ever disruption to global energy supplies. The U.S. paused the bombing last month but added a blockade of Iran's ports.
In the latest incident on the trade route, India said one of its ships had come under attack off the coast of Oman. It did not immediately give further details but said all the crew were safe.
Separately, the British maritime security agency UKMTO reported Thursday that "unauthorized personnel" had boarded a ship anchored off the coast of the United Arab Emirates port of Fujairah and were steering it toward Iran.
Security in that area is particularly sensitive, as Fujairah is the UAE's sole oil port on the far side of the strait, allowing some exports to reach markets without passing through it. Iran included that part of the coast on an expanded map it released last week of waters it claimed were under its control.
Iran has lately been letting the occasional ship pass through the Strait under special agreements. It let a Japanese tanker through Wednesday. Its Fars news agency reported Thursday an agreement to let some Chinese ships pass.
Iran's Judiciary Spokesperson Asghar Jahangir said Thursday the seizure of "U.S. tankers" violating Iranian regulations was being carried out under domestic and international law.
Little progress in talks
After intensively bombing Iran for six weeks, the United States and Israel paused their campaign more than a month ago to allow for what Trump said were promising peace talks. But after a single round of talks in Pakistan last month, there has been little progress and no further face-to-face meetings.
Trump had said his aims in starting the war were to destroy Iran's nuclear program, end its capability to attack its neighbors and make it easier for Iranians to overthrow their government.
But none of those objectives has been achieved so far, with Iran still in possession of more than 400 kilograms (900 pounds) of near-weapons-grade highly enriched uranium and missiles and drones with demonstrated ability to hit neighbors.
Iran's rulers, who had to use force to put down anti-government protests at the start of the year, have faced no organized opposition since the war began. And their newfound ability to close off the strait has given them additional leverage in negotiations.
Washington wants Tehran to hand over the uranium and forgo further enrichment. Iran is seeking the lifting of sanctions, reparations for war damage and acknowledgment of its control over the strait.
Trump's trip to China, initially scheduled for the end of March, was postponed because of the war at a time when Trump was predicting a quick end to it. In the end, he traveled with the standoff still unresolved, allowing it to loom over the first visit by a U.S. president in nearly a decade.
The United States hopes to convince China "to play a more active role in getting Iran to walk away from what they're doing now and trying to do now in the Persian Gulf," U.S. Secretary of State Marco Rubio told Fox News in an interview on board Air Force One en route to China.
"We've made clear to them that any support for Iran would obviously be detrimental for our relationship."