In the days leading up to the US and Israel’s war against Iran, Iranian commanders repeatedly warned their foes to expect a ferocious and escalatory response.
American military bases across the region would be hit, they said. The elite Revolutionary Guards conducted a naval exercise in the Strait of Hormuz, saying they were ready to close the key waterway. Gulf states urged US President Donald Trump to pursue diplomacy, not war, warning of threats to energy markets.
But the US appears to have underestimated the scale of Iran’s response. Almost two weeks into the war, Tehran has spread the conflict across the oil-rich Gulf, brought the flow of oil and gas shipments through the Strait of Hormuz to a trickle and sent global energy prices soaring.
“I can’t say that we anticipated, necessarily, that’s exactly how they would react, but we knew it was a possibility,” Pete Hegseth, US defence secretary, said this week.
Former US officials and military experts said Iranian forces had been able to use a combination of intelligence, lessons from Russia, satellite imagery and proximity to hit American bases, energy facilities and other strategic targets across the Gulf.
“No one has done more with less than the Iranians,” said Seth Krummrich, former chief of staff at US Soccent, the special forces command responsible for operations in the Middle East.
“Iran has precise intelligence when it comes to not only where we’re based, but a lot of our patterns of life and how we work as a military.”
Iran’s closeness to Gulf states means it can deploy its arsenal of short-range missiles and drones that can reach targets within minutes, providing little time for defences to react.
So far the vast majority have been intercepted, and western officials have applauded the Gulf states’ ability to defend against the threat. The US and Israel have also been relentlessly targeting Iran’s missile and drone sites as they seek to neuter the Islamic regime’s ability to strike back.
But Iran has hit American embassies in Riyadh and Kuwait City, US bases across the region, airports, data centres, hotels, a desalination plant, ports and oil and gas facilities, as well as residential buildings.
Iranian forces have fired more than 3,000 missiles and drones at the US’s allies in the Gulf and hundreds at Israel. This week they struck tankers and merchant vessels; an Omani port; sites close to Dubai’s airport; an oil refinery in Abu Dhabi and Kuwait’s airport — even as US and Israeli officials have said their capability to launch strikes has severely diminished.
Dana Stroul, former US deputy assistant secretary of defence for the Middle East, said Iran had been able to leverage a “pretty extensive intelligence network” in Gulf states. Qatar last week said it arrested 10 people belonging to two cells working for Iran’s Revolutionary Guards.
“Also, there’s so much commercial satellite image imagery available now that’s both available for purchase and then, of course, whatever they were receiving from the Russians and Chinese,” Stroul said.
Satellite image providers with US links curbed their commercial coverage of the region in recent days, with one imposing a 14-day delay on new images from the Middle East but satellite photos from before that remain widely available.
Stroul said Iran also gained experience from the 12-day war with Israel last year, when the US played a vital role in defending the Jewish state, as well as from its proxies that have for years sporadically targeted American forces and assets in Syria and Iraq.
In preparation for this war, the Trump administration deployed the biggest military force in the Middle East since the 2003 US-led invasion of Iraq. It dispatched two aircraft carrier strike groups and additional air-defence systems to defend Israel and the US’s Gulf allies.
But Kate Bondar, author of a study of Iranian drone warfare at the Center for Strategic and International Studies, said US air defences were not created to deal with the threat posed by Iran’s locally produced drones and missiles.
Bondar said the drones’ relatively slow speed and small radar signatures made them hard to distinguish from civilian aircraft, or even birds, on radar.
She said US planners appeared to have underestimated the threat posed by the drones, even though Russia has been using them in its war against Ukraine.
“They seem to have assumed this was something unique to the Ukrainian battlefield,” Bondar said.
Tehran appears to be relying increasingly on propeller-driven Shahed drones, powered by motorcycle engines, with 25-50kg warheads and made — in some cases — out of styrofoam.
These are far cheaper than missiles, easier to launch and harder to destroy on the ground, as launch rails can be mounted on pick-up trucks and rapidly relocated. They could hit precise targets using satellite navigation or even computer vision, experts said.
Unlike ballistic missiles, the drones fly low and do not follow predictable trajectories. Analysts say they can skim close to the surface of the Gulf, reducing radar visibility.
Yuri Lyamin, at the Moscow-based Centre for Analysis of Strategies and Technologies, said Iran’s initial strikes seemed aimed “primarily at blinding US forces and their allies in the region by destroying various radars”.
In the first days of the war, Shahed drones struck several military installations in the region. A US AN/TPY-2 radar in Jordan was destroyed and a large American-made AN/FPS-132 phased-array radar in Qatar was damaged, a former US military official said, based on satellite photos and videos.
A US satellite communications facility near the Fifth Fleet headquarters in Bahrain was hit in a strike captured in widely circulated video. One person formerly based at the site said the installation had already been decommissioned.
Satellite imagery of Prince Sultan Air Base in Saudi Arabia appeared to show damage to another early-warning radar of a Thaad battery, the US’s most sophisticated air-defence system, though it was partially covered by a tent. One US soldier died after an attack on the base.
The US military’s Central Command declined to comment on the targeting of radar systems.
Six US soldiers were also killed in a strike on a port in Kuwait.
General Dan Caine, chairman of the US joint chiefs of staff, said this week: “No plan survives first contact with the enemy . . . They’re adapting, as are we . . . We are adapting faster than they are.”
Experts say Iran has also learned from Russia’s wartime experiences with a version of the Shaheds in Ukraine. For instance, Lyamin said, Iran learned to launch drones towards the same target along different trajectories rather than in tight formations, making them harder to intercept.
Some Iranian drones appeared to incorporate Russian jamming-resistant technology, said Fabian Hoffman, an expert on missile warfare at the University of Oslo.
A Shahed launched at the UK’s Akrotiri air base in Cyprus on March 1 carried a Russian Kometa-M signal receiver, according to analysts, though UK officials say the case is still under investigation. US officials have said they believe Russia is sharing targeting information with Iran.
Robert Tollast, of the Royal United Services Institute think-tank, said it should have been no surprise that large static targets, such as fixed radar sites, were vulnerable to drone strikes.
Ukraine has been in talks with the US and several Gulf states about replicating Kyiv’s acoustic detection network to counter the drones.
Electronic jamming of satellite navigation signals — used in Ukraine to disrupt drones — had been deployed only selectively in the Gulf because of the risk of disrupting aviation and civilian infrastructure, Tollast said.
“A huge amount of civilian equipment and economic activity depends on satellite navigation,” said Tollast.
But he said the effectiveness of Iran’s drones would diminish rapidly as more solid drone defences were built.
Gulf states have relied largely on fighter jets and US air-defence systems, such as Patriot interceptors, to stop the Shaheds. The risk is that their stocks of expensive interceptor missiles — supplied by the US — run low in a war of attrition.
Iran has also kept up daily missile and drone barrages targeting Israel, although the volume and rate of fire has dropped significantly since the war’s first days.
Israel’s military says about two-thirds of Iran’s missile launchers have been “neutralised” in the war as it and US forces hit thousands of targets in the Islamic republic, raising questions about Iran’s ability to sustain the barrages..
Analysts note, however, that some of Iran’s most advanced missiles and drones have not yet appeared in the conflict.
This includes the Qassem Basir, a hypersonic missile with optical guidance, although Iran is only believed to possess a small number.
It is thought to have a stock of jet-powered Shahed-238 drones, which fly much faster, at 550km per hour compared with 185km per hour from the propeller-driven Shahed-136. One Shahed-238 was intercepted last week by air defences in the UAE.
Stroul said the US intelligence and military establishments — if not the politicians — would have anticipated much of what they are seeing.
Ahead of the war, Caine warned the White House about the risks of Washington being dragged into a protracted war, the complexity of the conflict and threats to American bases and personnel, according to US media.
Trump dismissed the reports at the time, saying his top commander believed it would be “easily won”.
This week, Trump told Fox News one thing that surprised him was that Iran “attacked countries that were not attacking them”, an apparent reference to Gulf states.
“Centcom understood what the escalation scenarios [were],” Stroul said. “It does not appear that President Trump and his inner circle fully grasped the escalation ladder and range of Iranian retaliation actions, and what the US options were going to be to counter them.”
Additional reporting by Neri Zilber. Data visualisation by Chris Cook and Jamie John, satellite image visualisation by Jana Tauschinski, cartography by Steven Bernard and illustration by Ian Bott