India’s security establishment has uncovered chilling details of Pakistan’s Inter-Services Intelligence (ISI) ultra-secretive “S1” unit—officially “Subversion 1”—that has masterminded terror strikes against India for over 25 years, from the 1993 Mumbai serial blasts to the recent Pahalgam tourist massacre in Jammu and Kashmir. Intelligence sources told NDTV that S1 is the ISI’s most potent engine of cross-border terrorism, headed by a serving Pakistani Army Colonel and run day-to-day by two operatives codenamed “Gazi 1” and “Gazi 2”. Headquartered in Islamabad and largely funded through narcotics trafficking, the unit maintains absolute deniability by operating in the shadows of multiple jihadi outfits.

S1 instructors are explosives virtuosos and weapons experts who possess detailed digital and physical maps of virtually every sensitive Indian target, sources revealed. Operating undercover with long beards and local attire, they embed themselves in training camps of Lashkar-e-Taiba, Jaish-e-Mohammed, Hizbul Mujahideen, and other groups without revealing their true identity. The secrecy is so airtight that most rank-and-file terrorists remain unaware they are being trained by Pakistani military officers. Over the past two decades, S1 has reportedly churned out thousands of battle-ready militants specifically programmed to strike Indian soil.

The unit’s fingerprints have surfaced in nearly every major attack traced back to Pakistan-based handlers, including the Pahalgam ambush that killed 26 tourists last month. Sources confirmed that S1 operatives personally oversaw the final training module for the three Pahalgam attackers inside a Jaish camp near Bahawalpur before infiltrating them across the Line of Control. The discovery has triggered a comprehensive re-examination of past strikes, with agencies now attributing a string of previously “unclaimed” operations directly to S1’s signature tactics.

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With the unit’s full operational grid finally decoded, Indian agencies have launched a multi-pronged counter-offensive involving diplomatic démarches, enhanced border drone surveillance, and targeted disruption of its drug-money pipeline. Security officials warn that S1 remains the ISI’s sharpest dagger aimed at India, capable of regenerating cells faster than they can be neutralised, making it the most dangerous state-sponsored terror apparatus Delhi has faced since the height of the Kashmir insurgency.

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