US President Donald Trump declared on Monday it “looks” like Iran was behind the attack on a Saudi Arabian oil facility.

American officials released satellite images of the damage to the oil processing plant and a key oil field. Two US officials said the attackers used multiple cruise missiles and drone aircraft.

Oil prices rose worldwide after the significant damage to the oil facilities and amid fresh concerns about war in the Middle East.

Trump restrained talk of quick military action, although earlier he had said the US was “locked and loaded.”

Iran denied involvement.

The attack stopped production of 5.7 million barrels of crude a day, which is more than half of Saudi Arabia’s global daily exports and more than 5% of the world’s daily crude oil production.

One US official said the US was considering increasing its military presence in the Gulf, but that no decisions had been made.

The US alleges that the attack did not come from neighboring Yemen, as claimed by Iranian-backed Houthi rebels there. A Saudi military claimed that “Iranian weapons” had been used.

The US ambassador to the United Nations, Kelly Craft, stated that “emerging information indicates that responsibility lies with Iran.”

Iran rejected the allegations, and a government spokesman said there now is “absolutely no chance” of a meeting between Iranian President Hassan Rouhani and Trump at the UN General Assembly next week.

“Currently we don’t see any sign from the Americans which has honesty in it, and if the current state continues there will be absolutely no chance of a meeting between the two presidents,” spokesman Ali Rabiei said.

The strike on the oil facilities have ratcheted up fear in an already tense environment in the Gulf. The attacks on oil tankers, which Washington blames on Iran, and the suspected Israeli strike on Shiite forces in Iraq, as well as the downing of a US drone by Iran, have all contributed to increased polarization. But the stage was set for these incidents by the re-imposed sanctions on Iran by the US after Trump pulled out of Iran’s 2015 agreement.