The US ordered some diplomats and their families to leave Saudi Arabia because of the threat from Houthi militants, as the Iran-backed group carried out more strikes from Yemen.

At least four people were killed by attacks on an Aramco oil site and an eastern airport on Wednesday.

The moves come as tensions escalate across the Middle East, with the US and Israel drawing up plans for renewed strikes on the Islamic Republic, according to the New York Times, and Tehran saying it struck more tankers going through the Strait of Hormuz. NBC News reported that the pullout of American personnel went beyond Saudi Arabia, with some military employees set to be removed from bases in Jordan, Kuwait and Qatar.

Oil and natural gas prices have risen further in the past two days, with Brent crude up 2.7% on Thursday to more than $111 a barrel, its highest level in five months.

“Iranian-supported Houthis have increasingly engaged in hostilities against Saudi Arabia, including attacks on civilian airports and other critical infrastructure resulting in civilian casualties and severe travel disruptions,” State Department spokesman Tommy Pigott said on Wednesday. “The safety and security of department personnel and their families remain our highest priority.”

A drone attack on Aramco’s Shaybah oil field killed two people from Nepal and the Philippines, early Wednesday, the Saudi Energy Ministry said. The projectile was intercepted, the ministry added, but the people were killed by falling debris. Operations at the field, which has the capacity to produce 1 million barrels of crude a day, were unaffected.

Two people were killed and several others were injured in an attack on King Fahd International Airport in the eastern Saudi city of Dammam later in the day, the General Authority of Civil Aviation said.

“We regularly move US service members and assets to optimize mission readiness,” a spokesman for Central Command, which oversees US forces in the Middle East, said when asked about the NBC report. “We do not discuss related movements for operational security reasons.”

The Houthis, a Yemen-based group that’s part of Iran’s so-called axis of resistance, have stepped up attacks on Saudi Arabia since early September. That’s led the kingdom to close many airports and cancel several investment conferences and entertainment events.

The Houthis, designated as terrorists by the US and European Union, control Yemen’s capital and territory holding around 70% of the country’s population. The Saudi government tried to oust them through a bombing campaign and support for other Yemeni armed forces from 2015 until a truce in 2022. That fell apart earlier this year when the Houthis accused the kingdom of blockading their ports and airports.

Beyond attacks on Saudi Arabia, the group has expanded its control along Yemen’s western coast in recent months, posing a greater threat to shipping through the Bab el-Mandeb Strait, another chokepoint for global trade.

President Donald Trump has so far resisted pressure to support the Saudis’ operations against the Houthis beyond providing intelligence. The UK and France have sent defensive military equipment, with the former this week saying it would deploy jets to help shoot down Houthi projectiles.

Iranian officials have said they expect the US to attack again and have warned they will retaliate fiercely. In the event of renewed attacks against its officials and civilians, Tehran will consider a “list of US political targets and war participants” as “legitimate targets,” the semi-official Fars news agency reported on Thursday, citing an unidentified senior security official.

The two sides agreed a ceasefire, called a memorandum of understanding, in June but it broke down after about two weeks. Since then, talks via Qatar and Pakistan, the main mediators, have failed to make much progress. Iran has continued to strike ships near or around the Strait of Hormuz and US President Donald Trump has threatened to renew full-on strikes against the Islamic Republic.

Israel, which launched the war on Feb. 28 alongside the US, has stepped up its rhetoric too, with Prime Minister Benjamin Netanyahu this week saying: “We must complete the elimination of the Iranian regime.”Iran says the US must lift a naval blockade and show it’s serious about reaching a diplomatic end to the conflict before serious peace talks can start.

Foreign Minister Abbas Araghchi urged the US to return to June’s MOU. Under that deal, the US lifted its naval blockade and Iran agreed to re-open the Strait of Hormuz, with conditions. Washington said it would in time release frozen Iranian oil funds and remove sanctions.

The deal broke down — resulting in the US reimposing the blockade — after Tehran started attacking ships that didn’t follow its preferred route through Hormuz.

“As we again find ourselves at a dangerous juncture, I am duty-bound to warn that any further escalation around the Strait of Hormuz or elsewhere in the region will put civilian lives and the well-being of all regional states and the global economy at great risk,” Araghchi wrote in the Financial Times.

On Thursday, Iran’s Islamic Revolutionary Guard Corps struck four “violating” tankers that were transferring oil in the northern Persian Gulf, Press TV reported, without elaborating on the dates of those attacks. The UK Maritime Trade Operations, an organization linked to the British navy, said a tanker was struck by a projectile southeast of Al Faw, Iraq, on Tuesday.

Despite the increasing frequency of Iranian attacks on merchant ships around Hormuz, oil flows from the Middle East show little sign of buckling. Shipments of crude and condensate from the Middle East, including those via pipelines that bypass Hormuz, have are not far off pre-war levels, according to ship-tracking companies.

Brent oil prices are more than 80% higher this year. Fuel pump prices in the US have soared, with diesel hitting a record high, which has contributed to the war’s increasing unpopularity among Americans.