Iran fired six ballistic missiles and 29 drones at Saudi Arabia's Prince Sultan air base in a Friday attack that injured at least 15 troops, taking the number of wounded US soldiers to more than two dozen in the last one week, and Yemen’s Houthis joined the Iran war by launching a missile at Israel early Saturday.

Five of the 15 injured in Friday’s attack were seriously injured, according to the people who spoke to The Associated Press on condition of anonymity. US officials initially reported that at least 10 US troops were injured, including two seriously wounded.

The base had come under twice earlier this week, including an incident that injured 14 US troops, according to the people who had been briefed on the matter.

Located about 96 km from the Saudi capital of Riyadh, the base is run by the Royal Saudi Air Force, but also used by US troops.

Houthis join war

Yemen's Iran-aligned Houthis confirmed on Saturday that they had launched an attack on Israel for the first time during the current Israeli-US war against Iran, marking their entry to the conflict and raising the prospects of a broader regional confrontation.

Israel said it intercepted the missile from Yemen, but few details were immediately available, including who fired it and at what target.

The group said the attack with a barrage of missiles came after continued targeting of infrastructure in Iran, Lebanon, Iraq and the Palestinian territories, adding that their operations would continue until the "aggression" on all fronts ends.

Weeks, not months: Rubio

US secretary of state Marco Rubio said Washington expected to conclude military operations within weeks, not months. The war, now in its fifth week, has spread across the Middle East, killing thousands and causing the biggest disruption ever to energy supplies, hitting the global economy and fuelling inflation fears.

Houthi involvement in the war would risk broadening and prolonging the conflict, given their ability to strike targets far beyond Yemen and disrupt shipping lanes around the Arabian Peninsula and the Red Sea, which they had done in support of Hamas in Gaza after October 7, 2023.

If the Houthis open a new front in the conflict, one obvious target would be the Bab al-Mandab Strait off the coast of Yemen, a key shipping choke point that controls sea ​traffic towards the Suez Canal, after Iran effectively shut the critical Strait of Hormuz.

Rubio told his Group of Seven counterparts in France that European and Asian countries that benefit from trade through the narrow Strait of Hormuz – a conduit for a fifth of global oil and natural gas supplies – should contribute to efforts to secure free passage.

The war has driven a wedge between the US and its traditional allies, who have stayed on the sidelines. US President Donald Trump said this lack of support had implications for Nato, the West's most important alliance.

"We would have always been there for them, but now, based on their actions, I guess we don't have to be, do we?" Trump told an investment forum in Miami on Friday. "Why would we be there for them if they're not there for us? They weren't there for us."

The charter underlying the North Atlantic Treaty Organization, which has long been led by the US, says an attack on one member is an attack on all, requiring them to support each other.

Rubio said Washington was "on or ahead of schedule in that operation, and expect to conclude it at the appropriate time here – a matter of weeks, not months".

While he said the US could achieve its aims without ground troops, he acknowledged it was deploying some to the region "to give the President maximum optionality and maximum opportunity to adjust the contingencies, should they emerge".

Washington has dispatched two contingents of thousands of Marines to the region, the first of which is due to arrive in coming days on a huge amphibious assault ship. The Pentagon is also expected to deploy thousands of elite airborne soldiers.

The deployments have raised concerns that the war could turn into a prolonged ground battle.

More strikes amid talk of negotiations

Stock markets tumbled sharply on Friday on fears the conflict will drag on, while the Brent crude oil benchmark topped $112, up more than 50 per cent since the war began.

In the US, diesel in California hit a record average high of $7.17 a gallon, the American Automobile Association said.

Trump has appeared eager to wind down the unpopular war, emphasising this week what he called productive negotiations aimed at a diplomatic solution – despite repeated assertions from Tehran that no such talks have begun. On Thursday, Trump extended a deadline by 10 days for Iran to reopen the Strait of Hormuz or face attacks against its civilian energy grid.

While those strikes were on hold, missiles and drones continued to rain down across the region.

Iran launched multiple waves of missiles at Israel overnight, killing one and causing several impacts in the Tel Aviv area from cluster munitions and debris from intercepted missiles.

At least five people were killed and seven injured after a US-Israeli attack on a residential unit in Iran's northwestern city of Zanjan, Iranian media reported early on Saturday. The Iran University of Science and Technology in Tehran was also struck, media reported.