The US military, he said, was working with its partners to "address this unprecedented attack and defend the worldwide rules-based order that is being undermined by Iran".
Trump said on Monday that it looked like Iran was behind the strike at the heart of the Saudi oil industry, but stressed he did not want to go to war. "We'll let you know, as soon as we find out definitively, we'll let you know", he said. He has said even if the sanctions are lifted, any talks must be held in the framework of the nuclear accord.
The Saudi government called the attack an "unprecedented act of aggression and sabotage" but stopped short of directly pinning blame on Iran. And just last week, senior State Department advisor Brian Hook wrote an op-ed in The Wall Street Journal arguing Iran "is effectively extending its borders, enlarging its sphere of influence, and launching lethal attacks against rivals" via the Houthis.
Trump, too, had talked more harshly at first. To the extent that duplicitous Saudi behavior enters into the equation at all, it seems to be quickly pushed aside in favor of backing a long-time ally merely because it has been a long-time ally-in the way that Sen.
However, Trump has said he is "locked and loaded" to respond to attacks on the Saudi oil plants.
"It wasn't an attack on us, but we would certainly help them", he said, noting a decades-long alliance linked to United States oil dependence that has lessened in recent years. "That was an attack on Saudi Arabia, and that wasn't an attack on us". "I'm not looking to get into new conflict, but sometimes you have to", he said.
Russian Federation and China said it was wrong to jump to conclusions about who was to blame for the attack on Saudi Arabia.
"What the photos indicate is that someone planned a sophisticated, coordinated attack that really impacted the production of oil at this facility", he said. "The thinking here is that any attack on Iran must set back Iran's military ability 10 to 15 years".
Sensing a commercial opening, President Vladimir Putin said Russia was ready to help Saudi Arabia by providing Russian-made air defence systems to protect Saudi infrastructure.
Saudi Arabia's King Salman visited Beijing in 2017, and Saudi Crown Prince Mohammed bin Salman came to China this year.
"I don't think there's a great independent Saudi capability to respond", he said.
The president also tweeted he had authorized the release of oil from the U.S. Strategic Petroleum Reserve, "if necessary", to minimise the effect of the strikes on global oil markets and keep pressure on Iran.
At the Pentagon, Defense Secretary Mark Esper suggested Iranian involvement, too.
"That's why all Iranian officials, from the president and the foreign minister to all others have announced that we do not negotiate (with the U.S.) either bilaterally or multilaterally".
In the immediate fallout from the attacks, state-owned producer Saudi Aramco told some Asian refiners it would meet its oil commitments, albeit with changes, sources said. But the United States has sought to put the blame exclusively on Iran - which says it was not involved - and President Donald Trump on Monday said his government was "locked and loaded" and ready to respond.
"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.
However, the president told reporters in the Oval Office that the U.S. "is prepared" if the attacks warrant a response.
"That was a very large attack and it could be met with an attack many, many times larger very easily by our country".
Saturday's attacks were the latest in a series of escalatory moves witnessed since the United States unilaterally withdrew from a nuclear deal with Iran and other world powers in May 2018 and slapped sanctions on Iran's oil and banking sectors in a "maximum pressure" campaign against it. It was the worst such attack on regional oil facilities since Saddam Hussein torched Kuwait's oil wells during the 1990-91 Gulf war.
U.S. stocks were down but only modestly.
The attack on the Abqaiq oil facility appears to have been carried out with drones operated by Houthi rebels in Yemen. But Khamenei said any talks with the Americans would lead to the "imposition of their demands on Iran" and mean their policy of "maximum pressure" was a success.