Trump has arrived in Beijing ahead of talks with President Xi Jinping.
He is expected to ask for China's help to resolve the costly and unpopular conflict, which he launched in late February, but analysts say he is unlikely to get the support he wants.
New reports have highlighted how the Iran war is accelerating geopolitical realignment across the region.
Israel said Prime Minister Netanyahu secretly travelled to the United Arab Emirates in March for talks with Sheikh Mohammed bin Zayed, which Israel said resulted in an "historic breakthrough" in Israel's relations with the UAE.
The two nations re-established ties in 2020 as part of the Trump-backed Abraham Accords, but the relationship has strengthened after the UAE came under Iranian attack.
But the UAE's foreign ministry denied the trip took place.
"Any claims regarding unannounced visits or undisclosed arrangements are entirely unfounded unless officially announced by the relevant authorities in the UAE," it said in a statement.
Iran, which has struck the UAE more than its neighbours in response to the US-Israeli attacks, hit out at the UAE.
"Enmity with the Great People of Iran is a foolish gamble. Collusion with Israel in doing so: unforgivable. Those colluding with Israel to sow division will be held to account," Foreign Minister Abbas Araqchi wrote on social media platform X.
Separately, Reuters reported that Saudi fighter jets have bombed Iran-backed militias in Iraq, part of a broader pattern of military responses involving Gulf nations during the war that have remained hidden.
Retaliatory strikes were also launched from Kuwait into Iraq, sources said.
Tehran, meanwhile, has tightened its grip on the Strait of Hormuz, which before the war handled one-fifth of the world's oil supply, cutting deals with Iraq and Pakistan to ship oil and liquefied natural gas from the region, according to sources with knowledge of the matter.
An Iranian army spokesperson said supervision of the waterway could generate revenue amounting to twice Iran's oil income, while strengthening its foreign policy leverage.
"After this war ends, there will be no place for retreat," the spokesperson said, according to comments carried by ISNA news agency.
More than one month after a tenuous ceasefire took effect, US and Iranian demands to end the war remain far apart.
Global oil supply will fall by around 3.9 million barrels per day in 2026 and undershoot demand due to disruptions caused by the Iran war, the International Energy Agency said, with more than one billion barrels of Middle East supply already lost.
The Trump administration said on Tuesday that senior US and Chinese officials had agreed in April that no country should be able to charge tolls on traffic through the region, in an effort to project consensus on the issue ahead of the summit.
On Wednesday, a Chinese supertanker carrying two million barrels of Iraqi crude sailed through the Strait of Hormuz, ship-tracking data showed, marking the third known passage by a Chinese oil tanker through the channel since the US and Israel launched strikes on Iran on February 28.
Iran has demanded security guarantees for Lebanon as part of its proposal to end the wider war.
But despite a US-mediated ceasefire announced in April, Israel has continued to strike Hezbollah.
On Wednesday, Israeli air strikes on cars in Lebanon killed 12 people, including two children, according to Lebanon's health ministry.
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