Trump criticised the lukewarm response to his call for world powers to send warships to escort tankers through the strait, which normally carries a fifth of global crude oil, demanding a more enthusiastic response.

Global oil prices have surged by 40 to 50 percent as Iran attacks shipping in the Strait of Hormuz and launches waves of missile and drone strikes in the Gulf in retaliation for the war launched by the United States and Israel on February 28.

The conflict has also spread to Lebanon, where Israeli forces have carried out strikes and launched a "limited" ground incursion that Western leaders warned Monday should not become a large-scale operation.

Trump said he thought Britain and France would get involved in efforts to secure the Strait of Hormuz -- but only reluctantly.

"We strongly encourage the other nations to get involved with us and get involved quickly and with great enthusiasm," Trump told reporters at a White House event.

British Prime Minister Keir Starmer said London was working with allies to craft a "viable" plan to reopen the strait, but ruled out a NATO mission, while Berlin also said it "has been clear at all times that this war is not a matter for NATO".

Japan, Australia, Poland, Spain, Greece and Sweden also all distanced themselves from any military involvement in the Strait of Hormuz.

EU foreign ministers discussed the war in Brussels on Monday but showed "no appetite" for extending their Red Sea naval mission to help reopen Hormuz, the bloc's top diplomat said.

Trump told the Financial Times on Sunday that it would be "very bad for the future of NATO" if they refused to help. He said Monday he has asked to delay a summit with Chinese leader Xi Jinping by a "month or so."

- Lebanon ground assault -

On another key front in the wider war, Israel announced "limited ground operations" against Iran-backed Hezbollah in southern Lebanon "aimed at enhancing the forward defence area".

Lebanon was drawn into the Middle East war on March 2 when Hezbollah attacked Israel in response to the killing of Iranian supreme leader Ayatollah Ali Khamenei.

Lebanese authorities said Israeli attacks have killed 886 people since the war erupted, with more than a million people registered as displaced.

The leaders of five Western countries said in a joint statement Monday that a large-scale Israeli ground operation in Lebanon "must be averted".

- Iranian defiance -

Explosions hit the Iranian capital on Monday as air defence systems were activated, an AFP journalist said, and Israel said it had also targeted the cities of Shiraz and Tabriz.

But Tehran's foreign minister struck a defiant tone.

"By now they have... understood what kind of nation they are dealing with, one that does not hesitate to defend itself and is ready to continue the war wherever it may lead, and take it as far as necessary," Abbas Araghchi told reporters in Tehran.

Iran's Revolutionary Guards threatened to target US companies in the region, warning employees to evacuate, after the Iranian foreign minister issued a defiant warning to Washington.

A drone sparked a fuel tank fire near Dubai airport, disrupting travel, while a missile killed a civilian in their car in Abu Dhabi, and another drone sparked a blaze in an area housing oil infrastructure in the eastern emirate of Fujairah.

The UAE's state-owned energy giant ADNOC halted the loading of oil into storage tanks at Fujairah, while a drone strike caused a fire at the major Shah oil field.

A Pakistani oil tanker was able to transit the Strait of Hormuz on Monday with its location transmitter activated -- suggesting it may have negotiated safe passage.

- Saudi, UAE call -

The war has engulfed much of the region, with Iran striking at least 10 countries that host US forces. Its Revolutionary Guards say it has fired some 700 missiles and 3,600 drones.

Saudi Arabia intercepted more than 60 drones overnight, its defence ministry said Monday, and Iraqi authorities said rockets wounded five people the day before at Baghdad's airport, which houses a US diplomatic facility.

Despite the violence and 17 days of internet blackout, some Iranians have sought to restore a sense of normalcy, with cafes and restaurants reopening and the popular Tajrish bazaar busy over the weekend ahead of the upcoming Persian new year.

There is little sign of a popular uprising within Iran, where security forces killed thousands during protests in January.

More than 1,200 Iranians have been killed by US and Israeli strikes, according to the last toll from Iran's health ministry on March 8, which could not be independently verified.

The UN refugee agency says up to 3.2 million people have been displaced in Iran.