U.S. military and intelligence officials were stunned at the precision, scale and sheer boldness of what they later concluded was an Iranian attack.

Four months ago, a swarm of low-flying armed drones and cruise missiles struck oil tanks in the central hub of the Saudi petroleum industry, catching Washington by surprise and temporarily knocking out 5% of the world’s oil supply. Almost no country in the region — Israel may be the exception — could have defended against it.

The Iranian attack on U.S. military posts in Iraq early Wednesday, local time — the only direct attack on the United States or its allies claimed by Iran since the seizure of the U.S. Embassy in 1979 — relied on ballistic missiles and inflicted little damage.

But with tensions between the United States and Iran at the highest level in four decades, the unexpected success of the September strike on the Saudi oil facilities is a stark reminder that Tehran has an array of stealthier weapons in its arsenal that could pose far greater threats if the hostilities escalate.

Iran has denied responsibility for the Saudi attack. But U.S. officials have concluded Iran was behind it, by sending the drones and missiles from Iran or southern Iraq.

Aftermath of the killing of Iranian Gen. Qassem Soleimani

Iran’s conventional military has deteriorated severely during the country’s relative isolation since the Islamic Revolution of 1979. But Tehran has spent those decades cultivating less conventional capabilities that are now among the most potent in the world and which are ideally suited for carrying out asymmetrical warfare against a superpower like the United States.


Iran commands one of the region’s largest arsenals of ballistic and cruise missiles, a network of allied militant groups around the region with as many as 250,000 fighters, and teams of computer hackers that American officials rank among the most dangerous.

It has also developed sophisticated armed and surveillance drones. And lacking a strong conventional navy, it has sought other ways to choke off the flow of Persian Gulf oil, with a fleet of small speedboats and a stockpile of underwater mines.

“Their offensive capability is drastically greater than the defensive capability that is arrayed against them,” said Jack Watling, an analyst at the Royal United Services Institute, a London security research center. “Their ability to inflict significant damage makes the cost of war with Iran quite severe.”

Aftermath of the killing of Iranian Gen. Qassem Soleimani

The ineffectual attack Wednesday demonstrated the range of Iran’s ballistic missiles — some traveling more than 600 miles — but also their poor accuracy, with several landing well outside their presumed targets. Some analysts suggested that Iran’s supreme leader, Ayatollah Ali Khamenei, may have intentionally ordered a symbolic but relatively harmless attack to show Iranian citizens a forceful response without provoking an all-out war with Washington.

“Khamenei has to calibrate the response so that it is enough for Iran not to lose face but not so much that Iran loses its head,” said Karim Sadjadpour, a scholar of Iran at the Carnegie Endowment for International Peace.

But Tehran and its allies may still be plotting less overt forms of revenge for the American killing last week of Iranian military commander Qassem Soleimani. Many analysts contend that Iran and its militant allies are reverting to their pattern of covert or indirect attacks that leave no clear evidence of Iranian responsibility.


Iranian-backed militias in Iraq, who also lost one of their leaders in the drone strike that killed Soleimani, said Wednesday that they would seek their own revenge. Hassan Nasrallah, leader of Iranian-backed Lebanese militia Hezbollah, has said that it would do so as well.

Iran has also shown a long-standing interest in assassinations, a tactic that could match the vows of Iranian officials to take “proportionate” measures to avenge Soleimani. Several Iran experts said that killing an American official, presumably in the region, might be the eye-for-an-eye that Tehran is seeking.

“I certainly would not be going out to many public places, because the risk of getting whacked or kidnapped is very high,” said Sir John Jenkins, a former British ambassador in Saudi Arabia.

But Iran has a dismal success rate in assassinating foreign officials.

Iran has tried and failed to kill Israeli diplomats in Thailand, Georgia and India, and to bomb a rally near Paris where Rudy Giuliani, the former mayor of New York, was speaking. In 2011, U.S. law enforcement agents broke up a particularly brazen and inept Iranian plot to hire thugs from a Mexican drug cartel for $1.5 million to blow up an Italian restaurant in Washington in order to kill a Saudi diplomat.

“We almost couldn’t believe it,” said Ilan Goldenberg, a former Pentagon official who oversaw its Iran task forces at the time. “Everybody looking at the intelligence thought it was just crazy noise, until a first payment of $150,000 showed up in a bank account.”


The September attack against Saudi Arabia presented a frightening alternative, in part because it exposed a vulnerable spot in most missile-defense systems. Most are built to defend against ballistic rockets, and almost none are equipped to detect and stop a large number of low-flying, high-speed drones and cruise missiles.

Officials said that the attack demonstrated that Iran’s technology was more advanced than U.S. intelligence agencies had expected.

“The attack on oil fields in Saudi was stunning in the depth of its audaciousness,” Gen. Kenneth F. McKenzie Jr., head of the Pentagon’s Central Command, said in a recent interview.

Tal Inbar, former director of the space research center at the Fisher Institute for Air and Space Strategic Studies, a now-closed Israeli research organization, said the precision of the attack could not have been achieved using only a GPS system.

“Much better capabilities were deployed in this attack,” he said, “possibly a camera on the missile and the drones, which compares reality with a target image.”

Unlike more advanced American or Chinese drones, Iranian drones cannot fire missiles from the air. But they can be loaded with explosives, as they were thought to be in the Saudi attack, to become remote-guided missiles.


Iran’s longest-range cruise missiles can strike more than 1,500 miles from Iran’s borders, reaching almost anywhere in the Persian Gulf. China, Russia and North Korea have provided Iran with technology and munitions, and Iran has produced remote-controlled drones domestically.

Until recently, though, Iran has preferred to rely on its network of militant allies around the region — including Hezbollah in Lebanon, an array of Iraqi militias now organized as the Popular Mobilization Forces, the Houthis in Yemen, and other groups across the region. Some, like Hezbollah or the Iraqi forces, are now so large, well-equipped and institutionalized that they more closely resemble professional militaries than informal militias.

“That is what extends Iran’s power far beyond its borders,” said Afshon Ostovar, a scholar of the Iranian military at the Naval Postgraduate School in Monterey, California.

The Trump administration’s sweeping economic sanctions on Iran over the past year have damaged its economy and reduced its ability to fund its militant allies. But a report this week from the Center for Strategic and International Affairs concluded that the total number of fighters in the full network of Iranian-backed militias has continued to grow steadily, to an estimated range of nearly 150,000 to more than 250,000.

And despite the efforts of the United States and Israel, Iran has continued to smuggle missiles of various ranges and abilities to its proxies in Syria, Iraq, Lebanon and Yemen, according to Israeli and U.S. defense officials.

The latest cycle of attacks between the United States and Iran started with a rocket attack that killed an American contractor in Iraq. The United States retaliated with a strike on an Iranian-backed militia, beginning a cycle of escalation.


But far from ending such rocket attacks, some of the Iranian-backed militias in Iraq have said that even without Iranian encouragement they now intended to step up their attacks on U.S. forces in order to drive them out of the country.

“I think we are settling in for what is going to be a bumpy period of conflict,” Ostovar said.

Cyberattacks — a weapon that can cause severe damage halfway around the world with low costs and few fingerprints — may be Iran’s wild card. Cybersecurity experts and government officials have already spotted an increase in malicious activity by pro-Iranian hackers and social media users that they believe could foreshadow more serious computer attacks from Tehran.

U.S. officials and independent cybersecurity experts say that Iranian malware attacks on Saudi Arabia have been among the most damaging of such assaults in history, causing at least tens of millions of dollars in damages.

A 2012 attack that U.S. officials attributed to Iran overwrote the hard drives of Saudi state oil company Aramco with the image of a burning American flag. A second attack in 2016 and 2017 destroyed files of the Saudi central bank, certain government ministries and several private companies. That time, a famous photograph of a drowned Syrian refugee child appeared on computer screens.

Former Director of National Intelligence Dan Coats ranked Iran as one of the four most dangerous sources of cyberthreats last year, along with Russia, China and North Korea.


“It is capable of causing localized, temporary disruptive effects — such as disrupting a large company’s corporate networks for days to weeks — similar to its data deletion attacks against dozens of Saudi governmental and private-sector networks,” he said.

One apparently low-level Iranian attack has already sought to avenge Soleimani. Iranian hackers temporarily captured the website of the U.S. government’s Federal Depository Library Program and replaced its contents with a eulogy for the general.

“Hacked by Iran Cyber Security Group Hackers,” text on the website read. “This is only small part of Iran’s cyber ability!”