A helicopter belonging to Saudi oil giant Aramco crashed on Sunday in Ras Tanura on Saudi Arabia's eastern coast on the Gulf, west of the Strait of Hormuz, killing 14 nationals, the state news agency reported, adding that the cause was unknown.
Aramco had resumed crude oil loadings on Friday at its Ras Tanura terminal in the Gulf after they were halted for nearly four months.
"The relevant authorities have launched a full investigation to determine the cause of the crash," the state news agency added.
Aramco did not respond immediately to an emailed request for comment.
The incident took place at 6 a.m. local time (0300 GMT), the state agency said, without providing further details.
Saudi Arabia, the world's biggest oil exporter, has joined a rush to move cargoes after Middle East producers ramped up oil and gas output and exports ahead of an interim deal to halt the war between the United States and Iran.