Iran’s First Use Of ICBMs Raises Serious Questions About Remaining Arsenal

In a startling move that has military experts questioning their assumptions about Iranian capabilities, Iran attempted to hit the joint UK-US base on the Indian Ocean island of Diego Garcia with two intermediate-range ballistic missiles (IRBMs). While US officials assured the Wall Street Journal that the base was unscathed, the Iranian strike aimed at a target roughly 4,000 kilometers from Iran suggests that the range of Iran’s retaliatory capacity could be well beyond previous external estimates and claims made by Iran. 

According to two officials who gave the Journal a Friday-night scoop on the story, one missile had a mid-flight malfunction, while the other was engaged by an SM-3 interceptor missile fired from a US Navy vessel. It’s not clear, however, if that interceptor actually hit its target. Nor does the report indicate when the strike was attempted. 

While it’s home to a joint base, Diego Garcia is a British Overseas Territory. After the bombs started falling on Iran on Feb. 28, British Prime Minister Keir Starmer initially refused to allow the United States to use Diego Garcia and other UK bases in the campaign against Iran. He soon folded, announcing that the bases could be used for so-called “defensive” operations focused on hitting Iranian missile launchers targeting UK interests. On Friday, the permission was expanded to include supporting strikes on Iranian assets targeting the Strait of Hormuz. Also on Friday, Iran warned that the accommodation of US military maneuvering makes the UK a “participant in aggression,” adding that Iran “reserve[s] our inherent right to defend the country’s sovereignty and independence.”

Last month — three days before US-Israeli surprise attack – Iranian Foreign Minister Abbas Araghchi claimed that Iran had, of its own volition, “deliberately limited” the range of its ballistic missiles to 2,000 kilometers, or 1,243 miles. On the same day, Secretary of State Marco Rubio said Iran was “certainly trying to achieve intercontinental ballistic missiles” and is “headed in the pathway to one day being able to develop weapons that can reach the continental US.” 

There’s far more to reaching the ICBM threshold than just packing more propellant into a rocket. Because ICBM warheads spend part of their trajectory traveling in space, they require the engineering of a heat-shielded reentry vehicle, along with more sophisticated guidance technology. Last May, the Defense Intelligence Agency predicted that, if it chose to, Iran could have upwards of 60 ICBMs by 2035. “There’s a huge gap, I think, between where they are now and their ability to have anything that reaches the United States,” Defense Priorities’ Rosemary Kelanic told the Journal. 

For now, the bigger question is what kind of ballistic missile technology the Iranians are already packing. The Israeli Alma Research and Education Center had previously pegged Iran’s maximum range at 3,000 kilometers. This apparent debut of Iran’s IRBMs raises wider concerns than just Diego Garcia: If Iran can actually reach that island, it implies Iran could also take shots at targets as far away as Central Europe or Scandinavia.  

Bigger story here: implied range of an Iranian IRBM from a launch box in central Iran, with a range of ~4500 km (distance to Diego Garcia).

Theoretically could also target sites into Central Europe. pic.twitter.com/8KCQtsHPQ4

— OSINTtechnical (@Osinttechnical) March 21, 2026

Earlier this month, Iran’s Space Research Center in Tehran was blown up in an Israeli-claimed strike. The IDF said the facility “contained strategic laboratories used for research and development of military satellites for various purposes, including surveillance, targeting, and directing fire toward targets across the Middle East.”

The Iranian Space Research Centre in western Tehran has been heavily damaged by American Israeli strikes.

The facility is a key hub for Iran’s satellite and intelligence research.

– Al Jazeera pic.twitter.com/i4ZGlWFGlU

— The Daily News (@DailyNewsJustIn) March 15, 2026

Diego Garcia had already been in the ZeroHedge headlines before this new round of warfare on Iran started on Feb 28. President Trump has sounded alarms about the UK losing its grip on the island. Last year, the UK agreed to surrender sovereignty over Diego Garcia and the entire Chagos Archipelago to Mauritius, with the UK then taking out a 99-year lease of Diego Garcia. In January, Trump called the transaction an “act of total weakness,” apparently reneging on his supposed support — Rubio last year said Trump “expressed his support for this monumental achievement.” 

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