To Find Clues in Saudi Oil Attacks, U.S. Examines Missile and Drone Parts

WASHINGTON — American intelligence analysts and military investigators are examining a missile guidance mechanism recovered in Saudi Arabia that may provide clues as to the missile’s origins and flight path, as they continue gathering information to make the administration’s case that Iran was responsible for last weekend’s attack against Saudi oil facilities.

Analysts are poring over satellite imagery of the damage sites, and assessing radar tracks of at least some of the low-flying cruise missiles that were used. Communication intercepts from before and after the attacks are being reviewed to see if they implicate Iranian officials.

And, perhaps most important, forensic analysis is underway of missile and drone parts from the attack sites. The Saudis have recovered pristine circuit boards from one of the cruise missiles that fell short of its target, providing forensics specialists the possibility of tracing the missile’s point of origin, according to a senior American official briefed on the intelligence.

Within the administration, there is much discussion over what retaliatory action to take, if any, and whether such a response would appear to be doing the Saudis’ bidding. The question is a challenging one for President Trump, who first declared after the attacks that the United States was “locked and loaded,” but then softened his tone and said he would like to avoid conflict.

The attack is viewed as the most destructive strike to Saudi Arabia since it opened an offensive in Yemen more than four years ago. By Monday, the damage in Saudi Arabia helped drive world oil prices up 10 percent, the speediest increase in more than a decade. The attack closed facilities at Abqaiq and Khurais, which are responsible for most of the crude oil produced by the kingdom, the supplier of about a tenth of the worldwide total.

Defense Secretary Mark T. Esper and Gen. Joseph F. Dunford Jr., the chairman of the Joint Chiefs of Staff, have presented Mr. Trump with an array of military options — presumably both bombing targets such as the missile-launching sites and storage areas and covert cyber operations that could disable or disrupt Iran’s oil infrastructure.

A big concern is to ensure that any strikes be proportional and not escalate the conflict, particularly with world leaders gathering in New York next week for the United Nations General Assembly. Officials also voiced worry about the cost of doing nothing, at least openly, in response to attacks that have cut in half the oil production of one of Washington’s main allies in the Middle East.

American officials say they have no doubt that the drones and missiles used in the attacks were Iranian technology and components. But they have not yet released information on whether the strikes were planned and directed by Iran, and launched by Iran’s proxies in the region — or whether they actually were launched from Iranian territory.

Intelligence officials have ruled out Yemen as the origin of the attacks and do not believe they emanated from Iraq, either. That leaves Iran or possibly some vessel in the northern Persian Gulf as the staging ground.

Several American military and intelligence officials said they believed they would ultimately conclude that the attacks were launched from Iran. Officials have said Iran is almost certainly behind the strike, given the scope, scale and precision of the attacks.

One theory gaining traction is that the cruise missiles were launched from Iran and programmed to fly around the northern Persian Gulf through Iraqi air space instead of directly across the gulf where the United States has much better surveillance, the senior official said. But that has not been confirmed.

The rulers of Saudi Arabia appear in no rush to pinpoint the source of the attack or call for any specific response.

A Saudi military spokesman said Monday that the kingdom’s initial investigation had indicated that the weapons were Iranian-made and that the attack was not launched from Yemen. But so far the Saudis have lagged American officials in their willingness to openly blame Iran for carrying out the attack.

Underscoring its go-slow approach, the Saudi Foreign Ministry said in a statement that it intended to invite the United Nations and other international experts to visit the site of the attacks and participate in the investigations. “The kingdom will take appropriate measures based on the results of the investigation,” the statement said, suggesting that the Saudis would wait a prolonged period before taking action.

Analysts said Saudi Arabia might be reluctant to engage in a military confrontation before confirming the American response. The rulers of the kingdom may also be worried because the attack demonstrated ominous vulnerabilities in their air defense systems. Although Saudi Arabia is one of the biggest spenders in the world on military hardware, the damage from Saturday’s airstrike suggested scant preparation for a full-fledged air war.

Saudi rulers have at least once actively covered up an Iranian attack inside the kingdom to avoid making accusations that could lead to a clash. After a terrorist bombing at the Khobar Towers complex killed 19 United States Air Force personnel in 1996, scholars say, the Saudis deliberately sought to obfuscate Iran’s responsibility in an attempt to avoid a military conflict. (The United States still ultimately concluded that Iran was responsible.)

Michael J. Morell, a former acting director of the C.I.A., said in remarks at a speech in Northern Virginia on Monday night that if Iran was found responsible for directing or carrying out the attacks, that would amount to an act of war and the United States would “need to respond.”

Mr. Morell, who said he had no inside information, said he favored some kind of proportional military strike, perhaps against Iranian missile sites and storage areas but not against Iranian oil infrastructure.

Adm. Michael G. Mullen, who retired from the military after serving as chairman of the Joint Chiefs of Staff, noted the danger of the situation because there was little effective way to communicate with the Iranians to avoid escalation and misjudgment.

“It’s a situation ripe with the possibility of miscalculation,” he said. “We have not had a good line of communication with Iran since 1979, so if something happens, the odds of us getting it right are pretty small.”

Mr. Morell said it would be important to have allies such as Britain and France join any retaliation so the United States was not going it alone.

France has no evidence showing where drones that attacked the Saudi oil facilities came from, the French foreign minister said on Tuesday.

“Up to now France doesn’t have evidence to say that these drones came from one place or another, and I don’t know if anyone has evidence,” the minister, Jean-Yves Le Drian, told reporters in Cairo.

Several top administration and military officials said they remained keenly aware of Mr. Trump’s reluctance to carry out military strikes that could pull the United States into a larger, longer conflict in the Middle East.