By Timour Azhari and Menna AlaaElDin
RIYADH, Oct 13 (Reuters) - A ballistic missile hit the headquarters complex of Saudi Arabia's state-owned oil company, the world's largest and the backbone of the kingdom's economy, a company source told Reuters, amid an escalating war between Yemen's Iran-allied Houthis and a Saudi-led coalition.
An office tower in the Saudi Aramco complex in the eastern city of Dhahran was struck on Tuesday night and the top three floors were damaged, the source said. The source and two other people with knowledge of the matter said the building was on fire.
The complex hosts a major operations centre for Aramco, which oversees a vast network of onshore and offshore oil rigs, pipelines, refineries and export terminals.
Earlier, six sources told Reuters they heard loud booms near the complex. There was no official comment from Saudi Aramco.
The Saudi-led coalition said fragments of a missile that it had intercepted and destroyed in Dhahran had fallen on a residential area, without providing further details.
Authorities also reported that drones and missiles were intercepted and destroyed in the capital, Riyadh, and the country's southern region.
The Houthis had earlier threatened a "harsh and painful" response to Saudi-led strikes on the Yemeni capital Sanaa, with spokesperson Yahya Saree saying targets could include the Saudi Aramco headquarters in Dhahran and an oil refinery in Riyadh.
The group has warned oil workers in Saudi Arabia to stay away from sites that could be targets.
The Houthis have for a week been firing ballistic missiles and drones at key Saudi sites in retaliation for the kingdom's backing of government forces against the Houthis in Yemen's reignited civil war. Riyadh’s international airport has received four strikes, including one on Saturday that killed 13 people.
The Houthis earlier on Tuesday said Saudi Arabia was attacking Sanaa, and the Saudi-led coalition warned civilians to stay away from an oil depot on the city's outskirts.
Houthi-run Al-Masirah television reported that the Saudi-led coalition had targeted the Yemen Petroleum Company's Sabah central station, a fuel depot on the outskirts of Sanaa.
The coalition said in a statement on Tuesday evening that it attacked the station and other sites in an operation aimed at "neutralizing the capabilities of Houthis" to threaten Saudi Arabia, Yemen and international waterways.
The Saudi cabinet, chaired by de facto ruler Crown Prince Mohammed bin Salman, issued a statement on Tuesday before the strike on Saudi Aramco saying the Houthis would face consequences for their repeated attacks on the kingdom.
Saturday's ballistic missile strike on Riyadh airport was the deadliest in Saudi Arabia in a decade, with further attacks grounding flights across the country even as it hosts a major energy conference.
REIGNITED YEMEN WAR
Saudi Arabia resumed its military campaign in Yemen in support of the internationally recognised government in a bid to reverse the Houthis' sudden gains last month, when they swept down the Red Sea coast to the critical Bab el-Mandeb Strait.
The strait, the southern gateway to the Red Sea, has become a more vital route for Saudi and other global energy supplies since the start of the Iran war in February, when Tehran closed the Strait of Hormuz leading from the Gulf to the Indian Ocean.
While a government offensive that began a week ago pushed the Houthis from the area closest to the strait, the group remains embedded nearby and has made gains around the city of Taiz this month.
Saudi Arabia has been seeking wider support from allies for its campaign against the Houthis and to help it ward off their missile and drone attacks.
Washington, Saudi Arabia's strongest ally and longtime security guarantor, has so far rebuffed Saudi efforts to bring it directly into the war against the Houthis.
The Yemen conflict has resumed as a spillover from the wider US-Iran war that began with the US-Israeli attack on the Islamic Republic on February 28.
Iran, Saudi Arabia's longtime regional archrival, has offered to mediate between Saudi Arabia and the Houthis, its foreign minister Abbas Araqchi said on Sunday in statements reiterated by the ministry on Monday.
(Reporting by Timour Azhari, Menna Alaa El Din, Yasmine Ghania, Tala Ramadan and Yomna Ehab; Editing by Andrew Heavens, Andrew Cawthorne, Cynthia Osterman, Sanjeev Miglani and Edmund Klamann)