A helicopter belonging to Saudi Aramco crashed at the company's Ras Tanura facility on Saudi Arabia's eastern coast early on Sunday, killing all 14 people on board, according to the Saudi energy ministry.

What happened

The crash occurred at around 6 a.m. local time at Ras Tanura, one of Saudi Arabia's most important oil export and refining hubs, on the Gulf coast, Al Jazeera reported, citing the energy ministry. The ministry said all 14 of those killed were Saudi nationals and extended its condolences to their families, as the Khaleej Times reported. Authorities did not immediately release the type of helicopter, the purpose of the flight, or further details of the victims.

Investigation under way

The energy ministry said an investigation had been opened with the relevant authorities to determine the cause, and officials did not speculate publicly about what had brought the aircraft down. There was no immediate word on whether operations at the sprawling oil complex were affected. Helicopters are routinely used across the oil and gas industry to move personnel and conduct inspections around large coastal and offshore facilities.

A critical oil site

Ras Tanura is a linchpin of global energy supply, home to a major refinery and one of the world's largest crude oil terminals. The facility had drawn attention in recent days for separate reasons: Aramco resumed crude loadings there late last week after a months-long pause. Authorities have not linked the helicopter crash to operations at the terminal, and the cause remains unknown pending the investigation.

This is a developing story and will be updated as Saudi authorities confirm further details.