Iran-backed Houthi rebels struck the headquarters of Saudi state-owned oil giant Aramco in an overnight attack, damaging the offices of its chief executive and other senior officials, two regional officials said.

The attack took place in Dhahran, an eastern Saudi Arabian city, and highlighted the rebels' ability to target major facilities in the kingdom.

No casualties were reported, but the strike damaged the building's top three floors, the officials said. They spoke on condition of anonymity because they were not authorised to discuss the matter publicly.

The Houthis had earlier warned that they were targeting Dhahran with a ballistic missile. Late Wednesday, the rebels' Al-Masirah television reported strikes on the Yemeni capital, Sanaa, blaming Saudi Arabia. The Saudi-led coalition did not immediately comment.

Smoke rising from some of Saudi Arabia's most sensitive facilities in recent days has alarmed the region and global markets. The attacks have also increased pressure on US President Donald Trump, who has said he is considering whether Washington should join Saudi strikes against the Houthis as the Iran war opens another front.

Saudi Arabia's Energy Ministry reported a "limited fire" at the Aramco building on Tuesday night. Aramco did not immediately respond to a request for comment.

On Wednesday, Saudi civil defence authorities in Riyadh said debris from an intercepted attack had injured one person. The state-run Saudi Press Agency published images showing a damaged building and a vehicle with a large cylindrical object, apparently part of a missile, lodged in its bonnet.

The Saudi-led coalition said it had intercepted two Houthi drones, four cruise missiles and one ballistic missile targeting Riyadh, another ballistic missile aimed at Dhahran and a cruise missile targeting Al-Kharj, an important military and industrial city.

Warnings of incoming missiles were also issued around Riyadh, although further details were not immediately available.

Houthis say attacks are retaliation for Saudi strikes

The Houthis described their attacks as retaliation for what they called "treacherous Saudi aggression" against Sanaa and other parts of Yemen.

Saudi Arabia is backing forces loyal to Yemen's internationally recognised government in a major military offensive launched about a week and a half ago. The Houthi-run Health Ministry reported two deaths in attacks in Yemen on Tuesday and blamed Saudi Arabia.

The rebels have repeatedly targeted Saudi airports, military installations and oil infrastructure. King Khalid International Airport in Riyadh has come under attack several times over the past week, with the strikes reportedly killing at least 18 people and injuring more than 300 others. The attacks have also severely disrupted air travel across the kingdom.

Hardened by years of civil war, the Houthis have emerged as one of Iran's most effective armed allies. However, analysts say the group also pursues its own interests. Its attacks have placed increasing pressure on Saudi Arabia, a key US ally.

Fighting intensifies along Yemen's front lines

The International Committee of the Red Cross has reported an "unprecedented surge" in combat casualties along Yemen's front lines, particularly in Marib, along the Red Sea coast and in the besieged city of Taiz.

The World Food Programme says it can no longer reach more than 600,000 people who depend on humanitarian assistance in Taiz.

Major roads leading into Yemen's third-largest city have been closed amid Houthi attacks. Clashes continue on the city's outskirts, accompanied by overnight bombardment.

Residents are increasingly concerned about shortages of food and fuel.

A Taiz resident, speaking by telephone on condition of anonymity because she feared the Houthis could seize the city, said long queues had formed outside shops and public transport had become increasingly scarce because of fuel shortages.

She said loud explosions were keeping her awake at night, although central Taiz had not come under shelling. Schools in the city were ordered to close for a month on Wednesday.

Houthis say mediation efforts are under way

A senior Houthi official told The Associated Press that regional and international powers had approached the group in an effort to stop its attacks on Saudi Arabia through a ceasefire agreement.

Mohamed al-Bukhaiti, a member of the Houthis' political bureau, said Oman had tried to bring the two sides back to the negotiating table, while Russia and China had also made efforts through Iran.

"We're welcoming any mediation that leads to an end of the war and the blockade between Sanaa and Riyadh," he said. "We're ready for a comprehensive end of the war and the blockade from both sides, not just a temporary ceasefire."

The rebels continued to threaten attacks on airports and oil facilities.

According to aviation analytics firm Cirium, more than 3,000 flights scheduled to depart from airports across Saudi Arabia had been cancelled or listed as not operating over the past week.

Saudi Arabia faces shortage of missile interceptors

The escalation has exposed Saudi Arabia's difficulties in intercepting Houthi missiles and drones. The kingdom has sought additional military assistance from allies, including the United States.

Regional officials said Saudi Arabia, the world's largest buyer of US weapons, was running low on missile interceptors.

Saudi forces are attempting to defend a territory roughly three times the size of Texas against daily attacks. Experts say intercepting every missile and drone is impossible.

The Houthis possess a large arsenal capable of striking targets more than 1,000 miles (1,600 kilometres) away. Some of their warheads can also change direction during flight.

Meanwhile, the Saudi-led coalition has continued striking oil-related targets in Yemen.

The Houthi-run Health Ministry said two people were killed in a Tuesday airstrike on an oil facility near the Ras Isa port in Hodeida province. The coalition also attacked another oil facility in Sanaa.

Ahmed Nagi, a senior Yemen analyst at the International Crisis Group, said attacks on fuel storage facilities in Houthi-controlled areas marked a new phase in the conflict. He warned that a prolonged war of attrition could severely weaken the rebels' military capabilities.

"The Houthis are betting on pressure, while the Saudis are betting on time," Nagi said.

The latest fighting has reignited Yemen's civil war after four years of relative calm.

"There’s a huge fear," said a Sanaa resident, Umm Shadi, following Saudi-led strikes on the city on Tuesday. She added that many people were staying at home.

UN staff member released by Houthis

A United Nations staff member detained by the Houthis has been released, the UN special envoy for Yemen said on Wednesday.

Hans Grundberg said Sami al-Kalabi, who was detained in June 2024, had been freed. The World Food Programme announced the release of one of its employees last week.

However, the Houthis continue to hold 71 UN workers who were arbitrarily detained over the past few years.

Aid workers are often held for months without charges and accused of spying for Western countries or Israel. Their families have denied the allegations.