A top-secret unit within Pakistan’s Inter-Services Intelligence (ISI), known as “S1”, has been directly involved in orchestrating terror attacks against India for nearly three decades, according to intelligence sources quoted by NDTV.

The unit, formally called Subversion 1, is said to be the ISI’s most critical division in running Pakistan’s cross-border terror operations. From the 1993 Mumbai blasts to the recent terrorist attack on tourists in Jammu and Kashmir’s Pahalgam, S1 has reportedly played a key role in funding, training, and directing militant activities inside Indian territory.

According to the report, S1 is commanded by a Colonel of the Pakistan Army, with two senior officers,identified only by their code names Ghazi 1 and Ghazi 2, supervising field operations. The headquarters of the unit are believed to be located in Islamabad.

Sources quoted by NDTV told that most of the unit’s terror funding comes from narcotics trafficking and other illegal activities. The network allegedly channels this money to militant groups operating in Jammu and Kashmir and other parts of India. The personnel in S1 are trained experts in bomb-making, specifically IEDs, and skilled in handling a wide range of weapons. Intelligence inputs further suggest that S1 maintains detailed maps of various Indian cities and strategic sites.

Operating For 25 Years

Security officials quoted by NDTV said the S1 unit has been active for over 25 years, though Indian agencies have only recently uncovered the full scope of its operations. S1 is believed to maintain direct links with several Pakistan-based terror groups, including Jaish-e-Mohammed (JeM), Lashkar-e-Taiba (LeT) and Hizbul Mujahideen.

Intelligence assessments indicate that S1 personnel frequently visit terror training camps run by these outfits. To conceal their identities, they reportedly adopt local appearances by keeping long beards and wearing ethnic attire, making it nearly impossible to distinguish them from ordinary recruits.

Officials familiar with counterterror operations said that S1’s secrecy is so tightly maintained that many of the militants trained by them are unaware of their trainers’ true identities or affiliations with the ISI. Over the last two decades, thousands of terrorists are believed to have undergone training under this covert wing.

The report further said that S1's involvement has been traced to almost every major terrorist strike carried out by Pakistan-backed elements in India. This includes the 1993 Mumbai bombings, the 2001 Parliament attack, the 26/11 Mumbai terror attacks, and several recent cross-border infiltration attempts in Jammu and Kashmir.

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India's Security Agencies Step Up Surveillance

The Indian intelligence agencies and counter-terrorism units, following the exposure of S1's role, have reportedly stepped up surveillance on suspected ISI operatives and terror modules linked to Pakistan. The officials believe that dismantling the funding and communication network of S1 would be crucial to curbing further attacks.

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While Islamabad has repeatedly denied any involvement in cross-border terrorism, the revelations about the S1 unit add yet another layer to the long-standing allegations of Pakistan's direct hand in training and exporting terror to India.