A missile and drone attack targeted the heart of Saudi Arabia's oil industry on Sunday in an assault claimed by Yemen's Houthi rebels, a new escalation in the six-year conflict.

The attack on energy giant Saudi Aramco's facilities came as the Saudi-led military coalition bombed Yemen's Houthi-controlled capital Sanaa after intercepting a separate flurry of cross-border Houthi drones and missiles.

The rising hostilities underscore a dangerous intensification of Yemen's conflict between the coalition-backed Yemeni government and the Iran-backed Houthis, despite a renewed US push to end the war.

The Houthi rebels claimed on Twitter they had fired drones and missiles at Ras Tanura, one of the world's biggest oil ports, and military targets in the eastern area of Dammam, as well as in southeastern provinces near the Yemeni border.

The Saudi defence ministry said it had intercepted a drone targeting a petroleum storage yard at Ras Tanura and a ballistic missile targeting Aramco facilities in the eastern city of Dhahran.

Shrapnel from the missile fell close to an Aramco residential compound in the city, which is home to thousands of company employees and their families, the energy ministry said.

The attacks did not result in any casualties or damage, it added, without specifying who was behind them.

The kingdom's oil-rich eastern region is home to most of Aramco's production and export facilities.

The defence ministry said the attacks targeted "the backbone of the world economy, oil supplies and global energy security”.

‘Red line’ 

On Sunday morning, the coalition pummeled Yemen’s Houthi-controlled capital Sanaa with air strikes, triggering huge explosions that sent plumes of smoke rising in the sky, according to AFP correspondents the ground.

"The military operation targets Houthis military capabilities in Sanaa and a number of other provinces,” the coalition said in a statement on Saudi state media.

That came after the coalition said it had intercepted a total of 12 drones and two ballistic missiles launched by the rebels, in a sharp uptick in cross-border attacks on the kingdom.

The coalition said the drones were aimed at "civilian” targets in Saudi Arabia, SPA reported, without specifying the locations.

The two intercepted missiles targeted the southern city of Jizan, the coalition added, without stating whether there were any casualties or damage.

The rebels have stepped up attacks on Saudi Arabia in recent weeks, as well as escalating an offensive closer to home, to seize the Yemeni government’s last northern stronghold of Marib.

In a statement after its strikes, the coalition said that targeting civilians in the kingdom was a "red line”, adding that the Houthis’ actions "will not lead to an imposition of a political settlement”.

The escalation comes as Washington resumes efforts for a resolution to the grinding conflict, which has claimed tens of thousands of lives and displaced millions, according to international organisations.

The United States last month delisted the Houthis as terrorists and stepped up efforts to resolve the six-year war.

The terror designation, imposed in the final days of the Trump administration, had been widely criticised by aid groups who warned it would hamper efforts to alleviate a humanitarian crisis in Yemen.

The coalition said the Houthis had interpreted their removal from the list "in a hostile way”, adding that coalition "victories” in Marib had prompted the rebels to step up their attacks inside the kingdom.

On Saturday, Yemeni government sources said fierce fighting between pro-government forces and the rebels in oil-rich Marib had killed at least 90 fighters on both sides over 24 hours.