Some Western embassy staff in Riyadh were meanwhile told to shelter in place, diplomatic sources said, following an attack on the US embassy compound earlier this week.

The war in the Middle East has engulfed the otherwise stable Gulf region as Iran retaliates against US and Israeli strikes that killed its supreme leader, launching attacks on Israel, the wider region and beyond.

At least 13 people have been killed in the Gulf, including seven civilians, since Iran began its strikes on Saturday. Washington said six US servicemen were killed, including four in Kuwait.

A fire broke out at Bahrain's Bapco Energies refinery following the Iranian attack but was later contained, the kingdom's communications centre said.

There were no reported injuries from the strike at the refinery on the island of Sitra and operations continued, the government media arm added.

Earlier, Britain said it was temporarily withdrawing some embassy staff and their dependants from Bahrain due to the security situation.

A witness said the diplomatic quarter in the Saudi capital Riyadh had been closed off after some Western embassy staff in Riyadh were told to shelter in place, diplomatic sources told AFP.

The witness and diplomats spoke on condition of anonymity to discuss the sensitive security matter.

On Thursday evening residents in Abu Dhabi reported hearing a series of loud explosions and authorities said air defences were responding to a missile threat.

Air defences also confronted a missile threat in the emirate of Fujairah, home to a major port where Iranian attacks have already targeted an oil storage and trading hub.

- Waves of explosions -

In an earlier barrage in the Emirati capital, six Pakistani and Nepalese nationals were injured, officials said.

Fresh waves of explosions, most from interceptions, also rocked Dubai, Doha and Manama on Thursday.

In Doha, AFP journalists saw a plume of smoke rising and reported loud blasts across the city.

Qatar's defence ministry said its forces intercepted 13 Iranian ballistic missiles on Thursday, while one fell in Qatari waters, and four drones were also shot down, with no casualties reported.

Earlier, Qatari authorities said they were evacuating residents living near Doha's US embassy.

Iran's ambassador to Saudi Arabia, Alireza Enayati, denied Thursday that Tehran was behind an earlier drone attack on the US embassy in Riyadh or strikes on the kingdom's vast Ras Tanura oil refinery.

"We confirmed that Iran has no role in the attack on the US embassy in Riyadh", he told AFP, adding that when Tehran's military carries out an operation "it takes responsibility for it".

Enayati also rejected suggestions Iran was waging a regional war. "It was imposed on the region," he said.

In Saudi Arabia, officials said they had intercepted three cruise missiles and several drones.

"Three cruise missiles were intercepted and destroyed outside the city of Al-Kharj," the Saudi defence ministry posted on X.

Elsewhere, a tanker was hit by a "large explosion" in waters off Kuwait, causing an oil spill, British maritime security agency UKMTO reported.

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