Tehran: Iran has sent the United States a diplomatic note denying any role in attacks on Saudi oil installations and warning of a response to any action, state media said on Wednesday.
A US official on Saturday said on condition of anonymity that Washington was certain that missiles that hit the close US ally and major oil exporter came from Iranian soil.
The attacks targeted Abqaiq, which is run by the Saudi state oil company Aramco and the Khurais oilfield.
The formal memo sent on Monday through the Swiss embassy, which represents US interests in Tehran, "emphasised that Iran has not played any role in this attack and denies and condemns" the US claims to the contrary, the official IRNA news agency said.
Iranian President Hassan Rouhani said that the attack was carried out in self-defence by Yemen's Houthi rebels, who enjoy backing from Tehran and have borne the brunt of a Saudi-led air campaign that has contributed to a humanitarian crisis.
Reiterating the tone set by US President Donald Trump, Vice President Mike Pence earlier said that "it's certainly looking like Iran was behind these attacks".
"As the president said, we don't want war with anybody but the United States is prepared," Pence said. "We're locked and loaded and we're ready to defend our interests and allies in the region, make no mistake about it."
The US assessment determined that "Iran launched more than 20 drones and at least a dozen missiles," according to unnamed sources.
The pre-dawn strikes follow earlier cross-border attacks on Saudi oil installations and on oil tankers in Gulf waters, but these were the most brazen yet, temporarily crippling much of the nation's production capacity. Saudi Arabia is the world's biggest exporter, shipping more than 7 million barrels of oil to global destinations every day, and for years has served as the supplier of last resort to markets.