US Drops 1,000-kg Bunker Buster Bomb on Isfahan, Massive Explosions Reported

Tehran/Washington: In a dramatic escalation of tensions in West Asia, the United States has reportedly carried out a high-impact airstrike on Iran’s strategic city of Isfahan, deploying powerful bunker-busting munitions targeting a suspected ammunition depot.

According to a senior US official quoted by The Wall Street Journal, the strike involved approximately 907-kilogram (around 1,000-kg class) penetrator bombs—commonly known as bunker busters—designed to destroy deeply fortified underground facilities. “A high volume of bunker busters, or penetrator munitions, was used for the strike,” the official stated.

Massive Secondary Blasts, Fireballs Illuminate Night Sky

Initial reports indicate that the strike triggered a chain of intense secondary explosions, suggesting the presence of stored munitions at the targeted site. Eyewitness-style visuals circulating online show towering fireballs, shockwaves, and thick plumes of smoke lighting up the night sky over Isfahan.

Shortly after the incident, former US President Donald Trump shared a video on his platform, Truth Social, appearing to capture the moment of impact. While he did not provide additional context, the footage shows successive detonations consistent with large-scale ordnance strikes and possible ammunition cook-offs.

WATCH: Overnight US strategic bombers, likely launched from Britain, dropped 2,000-lb bunker busters on a large Iranian Army ammunition depot near Mount Soffeh in the southwestern outskirts of Isfahan. Massive secondary explosions sent fireballs into the air. Trump also shared… pic.twitter.com/hvgoRWVW07

— Conflict Alarm (@ConflictAlarm) March 31, 2026

Why Isfahan Matters

The choice of Isfahan as a target underscores its immense strategic importance in Iran’s military and nuclear infrastructure.

Located along the Zayandeh River, the city is one of Iran’s prominent industrial and defense hubs, with a population of nearly 2 million. It hosts critical installations including the Badr airbase, which houses Iran’s fleet of ageing American-made F-14 Tomcats acquired before the 1979 Islamic Revolution.

More significantly, Isfahan is home to the Isfahan Nuclear Technology Centre—one of Iran’s primary nuclear research facilities. Established in 1999, the centre operates multiple research reactors, including Chinese-supplied units, and plays a central role in fuel production and nuclear material processing for Iran’s civilian programme.

The province also houses the underground Natanz enrichment site, widely regarded as a cornerstone of Iran’s uranium enrichment efforts.

Expanding Nuclear Ambitions

In February 2024, Iran announced plans to build a fourth research reactor in Isfahan, a 10-megawatt facility aimed at producing industrial radioisotopes and supporting nuclear material testing. Officials described it as part of the country’s peaceful nuclear development, though it has drawn international scrutiny.

Additionally, the city hosts the Iran Aircraft Manufacturing Industrial Company, a major aerospace and defense production hub involved in aircraft assembly, helicopter maintenance, and military equipment manufacturing.

A Repeated Target

Notably, the same site in Isfahan was reportedly struck during a brief but intense 12-day conflict last year, indicating its continued relevance in ongoing military calculations.

Rising Regional Tensions

The latest strike is likely to further inflame an already volatile regional situation, with fears of escalation growing amid ongoing hostilities. While US officials have not publicly confirmed operational details, the use of heavy bunker-busting munitions signals a willingness to target hardened and high-value infrastructure deep inside Iranian territory.

Iranian authorities have yet to release an official statement on the extent of damage or casualties.

(This is a developing story. More details are awaited.)