Explained: What Are Bunker Buster Bombs That US Used On Iran’s Fordow Nuclear Site Amid Escalating War With Israel

Washington: Amid soaring tensions in the Middle East, the United States on Sunday, June 22, executed a precision airstrike on Iran’s most fortified nuclear facility, Fordow, using one of the most fearsome weapons in its arsenal, bunker buster bombs.

The strike came amid deepening US involvement in Israel’s war against Iran, marking a dramatic military escalation. President Donald Trump called it a “very successful attack”, declaring that Fordow, the “crown jewel” of Tehran’s nuclear programme, was now destroyed.

What exactly are Bunker Buster bombs?

Bunker busters are powerful bombs designed to do what conventional explosives cannot, penetrate deep underground before detonating. These weapons are engineered specifically to take out fortified targets buried beneath concrete, steel, and rock.

The bomb used in Sunday’s strike was the GBU-57A/B Massive Ordnance Penetrator (MOP), the world’s most powerful non-nuclear bunker buster. Weighing nearly 14,000 kg, it was developed by Boeing to neutralise hardened underground facilities such as bunkers and nuclear sites.

Built with a high-strength steel alloy casing, the MOP is designed to survive high-speed impacts and tunnel deep into structures. It carries a 2,400 kg explosive payload and uses a delayed-action detonation system, meaning it explodes only after burrowing through protective layers, maximising damage from the inside out.

Equipped with GPS and inertial navigation, the MOP is highly accurate and can hit within metres of its intended target, even in hostile environments. It is capable of penetrating up to 60 metres of reinforced concrete or earth.

Why did US deploy Bunker Busters on Fordow?

Fordow, located beneath a mountain southwest of Tehran, is Iran’s most heavily guarded nuclear enrichment plant, a facility long viewed as beyond the reach of standard airstrikes. That changed on Sunday.

The US deployed B-2 Spirit stealth bombers, capable of breaching Iran’s air defences undetected, to deliver at least six GBU-57 MOPs directly onto the site.

The extent of the damage remains unverified, but the strategic impact is clear. The US has not only struck a critical Iranian nuclear facility but has also signalled its readiness to use advanced military force in Israel's defence.