Britain on Monday said an attack on Saudi Arabia's oil facilities was serious and outrageous but that the full facts were needed on who was responsible before making a response.
The attack "was a wanton violation of international law," British Foreign Secretary Dominic Raab said, adding that the United Kingdom stood firmly behind Saudi Arabia.
"In terms of who is responsible, the picture is not entirely clear," Raab said. "I want to have a very clear picture which we will be having shortly.
"This was a very serious attack on Saudi Arabia and the oil installations and it has implications for global oil markets and supply," Raab said. "It's a very serious, an outrageous act, and we need to have a clear and as united as possible international response to it."
US President Donald Trump said on Sunday the United States was "locked and loaded" for a potential response to the attack on Saudi Arabia's oil facilities, after a senior US administration official said Iran was to blame. Iran has denied it carried out the attack.