Riyadh, Saudi Arabia: Yemen's Iran-backed Houthi rebels on Tuesday claimed missile attacks on Saudi Arabia's Defence Ministry in Riyadh and the Ras Tanura oil refinery on the kingdom's eastern coast, as Saudi authorities reported intercepting incoming missiles and falling debris that damaged buildings and a vehicle in the capital.

Saudi Arabia, the world's largest crude oil exporter, has faced weeks of Houthi attacks targeting energy infrastructure and civilian sites, including Riyadh's international airport, amid escalating tensions in the Middle East.

Houthi military spokesman Yahya Saree said the group's forces had launched ballistic missiles at the Defence Ministry in the Saudi capital and the Ras Tanura refinery as part of a series of attacks on Tuesday.

"Our armed forces targeted the Ministry of Defence in the enemy Saudi capital, Riyadh, with a ballistic missile and the hit was direct," Saree said.

In a separate post, he claimed the group had struck the refinery in the Eastern Province, saying it was "able to target the Ras Tanura refinery in the Eastern Province with a ballistic missile". The attack caused "massive fires", he added.

Saudi authorities did not confirm the specific targets claimed by the Houthis. However, they said air defences intercepted two ballistic missiles launched towards Riyadh, with falling shrapnel damaging a building, a construction site and a car.

The Saudi-led military coalition fighting the Houthis said three additional missiles launched towards the Eastern Province had also been intercepted.

AFP correspondents in Riyadh reported hearing explosions on Tuesday. A mobile phone alert instructed residents to seek shelter as blasts rattled windows in the city centre.

Fire reported near key oil facility

Residents in the Eastern Province also reported explosions amid the reported attacks on the Ras Tanura complex.

A resident of Al Khobar, south of the refinery, told AFP that explosions were heard around dawn after a mobile phone alert was received.

"We got the alert on the mobile and then heard a very loud bang," the resident said.

Maritime security agency Vanguard reported a fire in the Ras Tanura area in the early hours of Tuesday following an attack.

"The fire has reportedly been contained, while the extent of damage and any impact on oil-loading operations remain unclear at current," Vanguard said.

Located along Saudi Arabia's Gulf coast, Ras Tanura houses one of the Middle East's largest refineries and is a critical component of the kingdom's oil industry. The facility has a processing capacity of 550,000 barrels per day.

The complex has previously been targeted in attacks attributed to Iran. A drone strike in March forced a partial shutdown of the refinery.

The Houthis also claimed to have targeted two military transport aircraft in southern Saudi Arabia with ballistic missiles on Tuesday.

Saree said the group had targeted the aircraft "with ballistic missiles, one at Najran airport and the other at (King) Khalid Air Base in Khamis Mushait". He added that a drone had been directed at Abha airport.

Houthis accuse Egypt of declaring war

Separately, the Houthis criticised Egypt's decision to authorise defensive military support for Saudi Arabia, with a senior official describing the move as a declaration of war against Yemen.

The Egyptian parliament approved the measure on Monday following a request from President Abdel Fattah al-Sisi. The precise nature of the proposed support remained unclear.

"It is truly remarkable that while these people go to discuss what they call 'peace in the region', Egypt and its parliament declare support for the so-called defence of the Kingdom of Saudi Arabia, and in doing so, declare war against the Republic of Yemen," Mohammed Ali al-Houthi, a member of the Houthi political bureau, said in a Telegram post.

The Houthi official also referred to a meeting in Tehran on Monday involving Saudi Arabia's Defence Minister, Pakistan's army chief and Turkey's intelligence chief, which was aimed at easing tensions amid the wider Middle East conflict.

Saudi Arabia, Turkey and Pakistan recently signed a NATO-style defence pact in Mecca, pledging to treat an attack on one member as an attack on all three.

Neither Turkey nor Pakistan has announced military strikes against the Houthis during the group's recent campaign against Saudi Arabia.

Al-Houthi said the rebels were "not afraid of any alliance that may be formed".

Conflict intensifies amid regional war

Yemen's largely dormant conflict reignited in July, adding another front to the regional instability surrounding the war between the United States and Iran.

The Houthis subsequently declared a maritime blockade against Saudi Arabia and began targeting its vessels, territory and oil infrastructure. The group also launched a major offensive in September, capturing large stretches of the Red Sea coastline.

The rebels have meanwhile reported repeated Saudi strikes against areas under their control, further intensifying the conflict as regional powers pursue diplomatic efforts to contain the wider war.