The Hidden Strength of Iran’s Missile Bases
Beneath the surface of central Iran lies a secret military facility known as the Yazd missile base. Located approximately 500 meters deep inside a mountain, this underground complex is more than just a bunker—it’s a fortress carved into one of the hardest rocks on Earth, Shirkuh granite. This rock is capable of withstanding immense pressure far beyond what conventional construction materials can handle.
This natural barrier presents a significant challenge for even the most powerful American bunker-busting bombs, such as the GBU-57 Massive Ordnance Penetrator. Inside the mountain, the space has been transformed into something resembling a hidden city rather than a typical military base. It is believed to have an automated rail system that connects assembly areas, storage depots, and multiple concealed exits within the mountain.
In Iranian propaganda videos, similar underground missile cities are shown with launchers being rapidly moved by lorries, fired, and then withdrawn back underground behind heavy armored doors. Despite weeks of intense US-Israeli strikes on these facilities, Iran continues to launch rockets and drones across the Middle East.
According to the Institute for the Study of War (ISW), the Yazd missile base alone has been hit at least six times since the start of Trump’s conflict with Iran, including on March 1, March 27, and 28. However, footage published by an OSINT account on March 28 appears to show two missiles being launched from the site, according to ISW reports. It remains unclear whether these launches occurred before or after the strikes.
Across Iran, similar underground “missile cities” have been constructed within mountains, forming a dispersed network of hardened sites that support the country’s ballistic missile capability. Experts suggest that the Islamic Republic has spent years building these cavernous bunkers to protect its vast missile arsenal from destruction.
Even after Israel’s 12-day war in June, which targeted Tehran’s infrastructure, the regime emerged with much of its stockpile of thousands of ballistic missiles intact. Recent US intelligence sources claim that Iran still possesses half of its missile launchers and thousands of drones. Three well-placed sources told CNN that the latest American intelligence assessments indicate Iran retains significant firepower, including inaccessible launchers buried by strikes but not destroyed.
Iran’s coastal defense cruise missiles, which allow it to threaten traffic in the Strait of Hormuz, are also thought to remain largely intact. While Israel estimated Iran had around 470 ballistic missile launchers at the beginning of the war, it claimed to have destroyed or disabled about 60% of them last month.
Despite extensive US and Israeli strikes targeting Iran’s missile infrastructure, the underground system remains largely intact. A recent CNN investigation found that while 77% of visible tunnel entrances had been hit, activity resumed quickly at those sites. Construction equipment was observed returning within days, clearing debris and reopening access routes into the mountains.
Reports describe cavernous halls filled with ballistic missiles, drones, and launch systems connected by transport corridors designed for rapid movement. A January 2026 assessment by Alma Research found similar data based on damage sustained during the 12-day war in June.
Footage released by Iran’s Fars News Agency showed long rows of missiles and Shahed drones lined up inside one such facility, with trucks carrying launchers positioned deep within the tunnels. Iranian flags hung from the ceilings, revealing the concerning scale of what has been built out of sight.
Many of the drones are relatively cheap and quick to produce, while the systems used to intercept them are far more expensive. Defending against such attacks can cost many times more than launching them, raising concerns about the strain on even well-equipped adversaries over a prolonged campaign.
However, experts say the real difficulty lies in penetrating the carefully-designed architecture where the weapons are stored. These underground complexes are designed for resilience, with tunnels segmented by blast-resistant doors to contain damage. Multiple entrances and exits allow operations to continue even if one or several access points are destroyed.
Some openings are decoys, and others are concealed within the natural contours of the terrain, making them difficult to identify and target. Even the most advanced bunker-busting weapons are constrained by the material they must penetrate.
Speaking to the Statesman, analyst Shanaka Anslem Perera said: “The mountain does not care how many sorties are flown above it. The railway does not care how many portals are sealed. The geology is the defense, and the geology has been there for 300 million years.”
Penetration depth varies depending on whether a target is covered by soil, concrete, or dense rock. Granite, in particular, absorbs and disperses explosive energy, reducing the effectiveness of even the largest conventional munitions.
According to RUSI, penetrating hardened underground facilities may require multiple strikes on the same point, detailed intelligence on internal layouts, and sustained follow-up attacks to prevent rapid repair. All of this must be carried out while suppressing air defenses and coordinating attacks across multiple dispersed sites.
Tunnelling expert Dr Amichai Mittelman said: “The mountains in Iran provide a level of protection 50-100 meters thick of rock that is hard to crack even by heavy bombs.” Targeting entrances has its limitations, as destroying an opening can block access temporarily, but does not collapse the network behind it.
The same logic applies to other potential weak points, such as ventilation holes. “The Iranians thought of everything, so they built many ventilation holes and shafts and installed fans to compress the air inside,” said Mittelman. “Sometimes this is a weak point for underground complexes – suffocation of those inside, but it is doubtful whether this is true for the large missile cities. The electrical infrastructure is also built on backups.”
Ground operations offer no easy alternative, and analysts note that inserting special forces into such deeply buried and complex tunnel systems would be high risk and difficult to scale. Experts say each site would need to be tackled individually, across multiple heavily fortified locations.
Tal Inbar, an expert on the Iranian missile program, said: “The effectiveness of a ground unit in such a facility is limited, and if you really want to solve the problem, you will have to send such a unit to each of these dozens of bases, which means it will be very difficult to succeed.”
Despite weeks of sustained bombing, Iran has continued to launch missiles at Israel and its Gulf neighbors throughout the conflict. In the latest escalation on Friday, the Islamic Republic unleashed a ferocious attack on Gulf energy sites, striking an oil refinery and desalination plant in Kuwait as well as a major gas complex in Abu Dhabi after boasting it had shot down a second American F-35 fighter jet.
The Islamic Revolutionary Guard Corps (IRGC) claimed the aircraft was attacked over central Iran by its air defenses, according to a statement carried by Mehr news agency.
Meanwhile, it is unclear how the conflict will be resolved, with Donald Trump threatening to bomb Iran “back to the Stone Age” this week while simultaneously claiming the gallant US military had already won. Trump vowed late on Thursday that the military “hasn’t even started destroying what’s left in Iran.” He wrote on Truth Social: “Our Military, the greatest and most powerful (by far!) anywhere in the World, hasn’t even started destroying what’s left in Iran. Bridges next, then Electric Power Plants! New Regime leadership knows what has to be done, and has to be done, FAST!”
And on Wednesday, the President said Iran’s “ability to launch missiles and drones is dramatically curtailed, and their weapons factories and rocket launchers are being blown to pieces, very few of them left.” The latest intelligence reports suggest a more limited effect, although Iran’s military has indeed suffered heavily.
As of Wednesday, the US had struck more than 12,300 targets inside Iran, according to US Central Command. US Defence Secretary Pete Hegseth has pointed to a dramatic reduction in the frequency of weapons being fired by Iran. He said on March 19 that the number of ballistic missiles and drones being launched were both down by 90% since the first days of the conflict.
At the same time, it is obvious Tehran has been planning for an attack like this for decades. The mullahs know they have several advantages over America’s military machine, not least their stranglehold over much of the global oil supply and the vulnerability of the US’s regional allies in the Gulf, who have been hit hard by Iranian strikes.
And this, combined with their lethal supply of hidden weapons, allows Tehran to set tough, probably impossible conditions even for talks to take place. A cessation of hostilities and an end to the killing of Iranian officials are reasonable enough demands, but “reparations” for damage caused by US bombing and a guarantee of Iranian sovereignty over the Strait of Hormuz will be too much for Washington to stomach.
Meanwhile, although the pace of Iranian strikes has slowed compared to the early days of the war, it has stabilized into a steady rhythm, suggesting that sufficient infrastructure remains operational.
Perera said: “The persistence of Iranian missile fire despite three weeks of intensive strikes is not resilience. It is infrastructure. IRGC did not prepare for this war by building rockets. It prepared by building railways inside mountains. The rockets are replaceable. The railways are permanent. And the granite that protects them was formed before mammals existed.”
“The strait is 21 miles wide. The mountain is 500 metres deep. And the railway inside it is still delivering missiles to the surface,” he added.
