The US embassy in Saudi Arabia has issued a warning about a potential militant plot to kidnap Western oil workers.
The warning said officials received information about a threat to kidnap the workers from oil fields in the kingdom's Eastern province.
The embassy said it had "no further information on the timing, target, location or method of any planned attacks".
From 2003 to 2007, al Qaida-linked militants carried out attacks in Saudi Arabia aimed at destabilising the Western-allied monarchy, including deadly bombings of residential compounds housing foreigners in Riyadh in 2003.
The kingdom is taking part in the US-led coalition against the Islamic State group.