President Trump announced an increase in sanctions on Iran on Wednesday after Secretary of State Mike Pompeo blamed the country for an attack on Saudi oil fields. Mr. Trump wrote on Twitter that he had asked the Treasury Department to "substantially increase" sanctions on Iran.

"I have just instructed the Secretary of the Treasury to substantially increase Sanctions on the country of Iran!" Mr. Trump wrote.

Saudi Arabia was expected to directly blame Iran on Wednesday for the raid that heavily damaged two oil facilities in the kingdom over the weekend. Pompeo was visiting Saudi Arabia to discuss the attack "and coordinate efforts to counter Iranian aggression in the region," according to the State Department.

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Pompeo tweeted on Sunday that "Iran has now launched an unprecedented attack on the world's energy supply," adding that there was no evidence that the attack came from Houthi forces in Yemen, who claimed responsibility.

"We call on all nations to publicly and unequivocally condemn Iran's attacks. The United States will work with our partners and allies to ensure that energy markets remain well supplied and Iran is held accountable for its aggression," Pompeo tweeted.

Iran has denied any involvement, but on Wednesday Iranian President Hassan Rouhani said Saudi Arabia should see the attack as a warning to end its war in Yemen.

CBS News national security correspondent David Martin said the most urgent order of business for Pompeo will be to discuss the installation of better air defenses around the Saudis' oil facilities, which have suddenly proven vulnerable to attack.

U.S. intelligence agencies were caught flatfooted, never expecting Iran would be so bold as to attack Saudi Arabia directly. A U.S. official told CBS News the U.S. has identified the exact locations in southern Iran from which the drones and cruise missiles were launched at Saudi Arabia's oil facilities.

Saudi Arabia's Crown Prince Mohammed bin Salman said Wednesday that his country was already beefing up its security measures in the air and the water. CBS News correspondent Ian Lee said the Saudis had also committed to joining a U.S.-backed force to protect vital shipping lanes and oil facilities in and around the Persian Gulf.

U.S. officials said experts have examined pieces of the wreckage on the ground, identified the specific type of cruise missiles and drones fired on Saturday and determined they were made in Iran. A senior administration official told CBS News there was "100%" certainty on that point.

Pompeo will ask the Saudis what they want to do in response to what U.S. officials have called "a complex and coordinated attack" on their infrastructure.

One option is a military strike against the facilities from which those drones and cruise missiles were launched.

"We're locked and loaded, and we're ready to defend our interests and our allies in the region, make no mistake about it," Vice President Mike Pence said Tuesday.

It was unclear on Wednesday whether Mr. Trump was favoring a military response, which would risk a dramatic escalation in the region.

"By sending your secretary of state, it almost implies that you're leaning more toward diplomatic solutions to this issue," Joseph Westphal, a former U.S. ambassador to Saudi Arabia, told CBS News. He said Pompeo's visit "will be important to ensure that both U.S. and the Saudis have a unified response to this attack."

Mr. Trump had talked about trying to strike a new deal with Iran since pulling the U.S. out of the 2015 nuclear agreement hashed out by his predecessor, but now he says he no longer wants to meet Iran's president when world leaders gather for the United Nations General Assembly next week.