The Middle East war intensified with Iranian-backed Houthis in Yemen launching strikes on several Saudi cities, further embroiling a US ally in the conflict, while US forces hit ⁠multiple Iranian oil tankers and Iran targeted a US base in Jordan.

The Houthis attacked four cities in the south of Saudi Arabia, wounding 73 people and setting oil installations ablaze in what appeared to be a major expansion of the six-month-old war.

As global oil markets were pricing in the Saudi attacks, the US military’s Central Command said it destroyed five Iranian crude oil carriers and posted video of the strikes, which it called a response to Iran’s Islamic Revolutionary Guard Corps targeting a U.S Navy warship with ballistic missiles twice over the previous two days.

No Americans were harmed, the US said.

US Secretary of State Marco Rubio said Washington would continue to strike them in response to Iranian attacks.

“Iran continues to try to hit US naval ships and for every time they do that or try to do that, they’re going to lose tankers,” Mr Rubio told reporters during a visit to Colombia.

Iran then retaliated with a ballistic missile attack on a US base near Al Azraq town in eastern Jordan, according to an IRGC statement carried on state media.

Iranian state media published video of what it said were Iranian missiles launched at Jordan.

Although Iran said its missiles inflicted heavy damage, Jordan said its ‌air defences intercepted 18 of the 20 Iranian missiles, with two falling in ⁠unpopulated areas, and that there were no casualties.

Iran has targeted US allies in the region throughout the war, including Jordan several times, killing two Us military personnel during one strike in July.

A separate IRGC statement said it also attacked two US destroyers, state media reported.

The US military had yet to respond to the reports.

Iran also threatened to target oil tankers in Kuwaiti and Bahraini ports, according to a statement carried by state media.

A maritime security source reported a liquefied natural gas tanker was damaged in the Emirati port of Khor Fakkan, but it was unclear who was responsible.

After a month of calm in August, Iran and the US resumed exchanging fire in recent days, driving the price of benchmark Brent crude oil to its highest level since 23 July 23.

But prices remained below $100 (€85) per barrel, despite the disruptions.

The war has been marked by a cycle of pauses followed by periodic flare-ups, with Iran still able to ‌launch missile and drone strikes on its neighbours and threaten oil shipping in ⁠the Strait of Hormuz despite US attacks that have degraded much of its conventional forces and extracted a toll on its already ailing economy.

The Houthis, who control most of Yemen’s populated areas including the capital, have further pressured US allies by periodically disrupting shipping on the other side of the Arabian Peninsula, at the entrance to the Red Sea.

Yesterday, the Houthis said they had launched a broad operation deep into Saudi territory, using drones and missiles to strike a Saudi airbase in the southern city of Khamis Mushait as well as Saudi state oil company assets in the cities of Abha, Najran and Jazan.

NASA satellite images showed a thick cloud of black smoke over the Jazan refinery and a column of white smoke rising from an oil distribution centre in Abha.

Saudi authorities described blazes at the ‌sites and said women and children were among the 73 people hurt.

The reports of such large numbers of wounded suggested the attacks were among the biggest carried out against Saudi Arabia since the United States and Israel launched their war against Iran in February.

Meanwhile, Iranian tankers came under assault, marking a resumption of US attacks on Iran ⁠after a two-day pause.

The US said it destroyed four IRGC crude oil carriers in the Gulf of Oman and a fifth near the oil hub of Kharg Island, after Iranian media had reported some of the attacks.

“American forces directed ‌the crews to abandon ship before the vessels were struck and rendered inoperable,” the Central Command statement said.

Houthi attacks on southwestern Saudi Arabia have the potential to worsen the war’s global economic impact by disrupting Middle East energy supplies beyond the blockaded Strait of Hormuz.

Saudi Arabia has led an Arab coalition battling against the Houthis in Yemen for more than a decade.

That war had calmed in recent years, but a ceasefire there has broken down.

In recent days, Saudi-backed Yemeni forces of a government based in the ⁠south have launched a multipronged offensive on Houthi-held areas after the Houthis tried to advance on government-held positions.

The government, which was driven by the Houthis from the capital 12 years ago, said it now aims to recapture all Houthi-held territory.

The wider war ⁠in the Gulf has turned into a test of wills between the US and Iran, with each side hoping that economic pressure from competing blockades will force the other to yield.

The US Treasury announced new aviation-related sanctions yesterday that it said were aimed at grounding Iran’s airlines.

Washington is trying to increase the flow of oil to world markets by guiding ships through the Strait of Hormuz, while cutting off Iran’s exports with a blockade.

Central Command said the tankers it destroyed were part of a shadow network that funds the IRGC and its regional proxies.

Iran has long supported what it calls an “Axis of Resistance”, which includes Hamas, Lebanon’s Hezbollah, Iraqi Shi’ite militias and the Houthis.

Iran’s Revolutionary Guards said they had captured a US submersible near the strait.

A US official said an underwater drone malfunctioned more than a day ago, adding it did not have classified sonar or radar equipment on board.

CENTCOM spokesperson Captain Tim Hawkins, without mentioning whether the device was seized by Iran, said: “An underwater drone operated by US forces malfunctioned more than a day ago.

“It was surveying regional waters in support of ongoing operations.”

He added the “defective drone was an older model that neither collected sensitive data nor carried any classified sonar or radar equipment”.

Iran’s Revolutionary Guards had said they seized a US underwater drone at the “entrance to the Strait of Hormuz in a complex intelligence and operational action”, describing it as “one of the most modern, unmanned and smart submarines” operated by US forces.