Why in news?

Iran launched two intermediate-range ballistic missiles targeting the US-UK military base at Diego Garcia — located approximately 4,000 km from Iran's coastline in the Indian Ocean.

This marks one of Tehran's longest-range strike attempts ever, sharply escalating the West Asia conflict beyond its regional boundaries and raising alarms in Washington and allied capitals worldwide.

What’s in Today’s Article?

• Background: What Exactly Happened?
• Why the Distance Matters?
• The Missile Used: Khorramshahr-4
• Diego Garcia and its Significance
• Missile Defence: The SM-3 System
• Iran's Broader Escalation Strategy

Background: What Exactly Happened?

• Iran fired two ballistic missiles at Diego Garcia. Neither hit its target:
  • One failed mid-flight;
  • The second was intercepted by a US Navy destroyer using an SM-3 missile interceptor — though whether the interception was fully successful remains unclear.
• Despite causing no physical damage, the attempt itself has triggered serious concern — it signals that Iran may now possess, or is willing to demonstrate, strike capabilities far beyond previously declared limits.

Why the Distance Matters?

• Diego Garcia lies ~3,800–4,000 km from Iran.
• Iran had long claimed its missile programme had a maximum range of ~2,000 km.
• This strike attempt effectively doubles that claimed range, suggesting Iran has significantly advanced its missile capabilities.
• If confirmed, it would be the first operational indication that Iran can strike targets at such distances.
• A 4,000 km strike radius from Iran would theoretically place within reach:
  • Large parts of Europe, including cities like Paris and London
  • This fundamentally changes the threat perception for NATO countries that had so far viewed the West Asia conflict as a regionally contained crisis

The Missile Used: Khorramshahr-4

• The Khorramshahr-4 itself is a liquid-fuelled missile capable of carrying a warhead exceeding one tonne, with the option of deploying cluster munitions.
• Its design, derived in part from earlier North Korean and Soviet systems, combines relatively simple architecture with high payload capacity.
• The missile is also believed to feature manoeuvrable re-entry capabilities, making interception more difficult.
• Assessed range - Potentially exceeds 4,000 km (previously undemonstrated).

Diego Garcia and its Significance

• 
• Diego Garcia, located in the central Indian Ocean in the Chagos Archipelago, is a key US military base and one of only two major bomber bases in the Indo-Pacific, along with Guam.
• It is operated jointly by the United States and the United Kingdom.
• Diego Garcia sits approximately 3,000 km from both the Bab-el-Mandeb Strait at the mouth of the Red Sea and the Malacca Strait near the South China Sea. 
• Strategic Importance
  • Serves as a critical logistics and operations hub for long-range military missions.
  • Has historically supported US bombing campaigns in Afghanistan, Iraq, and recent Middle East operations.
  • Its airfield can host:
    • Heavy bombers
    • Surveillance aircraft
    • Pre-positioned military equipment
  • Enables rapid military deployment across Asia, Africa, and the Gulf.
  • Additionally, it plays an important role in US Space Force tracking systems, enhancing its strategic significance.
• Ownership and Control of Diego Garcia
  • Historical Control and Lease to the US - Diego Garcia is part of the Chagos Archipelago, originally controlled by the UK. In 1966, the UK leased the island to the US for a military base for 50 years. The lease was extended in 2016 for 20 more years, initially up to 2036.
  • International Legal Dispute - In 2019, the International Court of Justice (ICJ) ruled that the UK’s separation of the Chagos Islands from Mauritius was illegal. It recommended that sovereignty should be returned to Mauritius.
• Current Status
  • In May 2025, the UK formally transferred sovereignty of the Chagos Islands to Mauritius.
  • However, Diego Garcia was leased back to the UK for 99 years at £101 million annually.
  • The move was partly driven by strategic concerns, including preventing rival powers like China from gaining access.

Missile Defence: The SM-3 System

• The attempted interception was carried out using the SM-3 interceptor, deployed on US Navy warships.
• The SM-3 uses a "hit-to-kill" approach — it destroys incoming missiles through kinetic force (physical impact), not explosives.
• It is well-established against short and medium-range threats, but the uncertainty around this interception highlights the challenges posed by advanced manoeuvrable ballistic missiles.

Iran's Broader Escalation Strategy

• The Diego Garcia strike is not an isolated event — it fits into a wider pattern of Iranian escalation:
  • Stepped-up attacks on energy infrastructure across the Gulf, including drone strikes on Kuwait's Mina Al-Ahmadi refinery.
  • Warnings issued to countries hosting US forces.
  • Iranian officials signalling that targets could extend beyond traditional battlefields.
• This points to a strategy combining conventional missile strikes with the threat of asymmetric warfare.