RIYADH — US Secretary of State Mike Pompeo denounced strikes on Saudi Arabia's oil infrastructure as an "act of war" on Wednesday.

"This was an Iranian attack," Pompeo told reporters on his plane before landing in Jeddah, calling it "an act of war".

Pompeo said there was no evidence the attacks had been launched from Iraq.

Pompeo later held talks with Crown Prince Muhammad Bin Salman, deputy premier and minister of defense, to weigh with the US ally a response to the strike.

A US official, speaking on condition of anonymity, said the administration has concluded the attack involved cruise missiles from Iran, and evidence would be presented at the UN General Assembly next week.

"As the president said, we don't want war with anybody, but the United States is prepared," Vice President Mike Pence said on Tuesday. — AFP