There are two jihadi terrorist organisations by the name the 313 Brigade. The first is Kashmir-centric and is associated with the Harkat-ul-Jihad-al-Islami (HUJI) of Qari Saifullah Akhtar. It has been in existence since at least 1999 and is a member of the United Jihad Council, based in Pakistan-Occupied Kashmir, which is headed by Syed Salahuddin of the Hizbul Mujahideen. It looks upon India as its main enemy and is not against the government of Pakistsan, its Army and the Inter-Services Intelligence (ISI).
On December 15, 1999, a Rashtriya Rifles unit in Jammu & Kashmir had killed one Sher Khan, who was described as the chief commander of a newly formed 313 Brigade and a HUJI commander called Nadeem Khan during an encounter in the Marot forest area of Surankote. The Excelsior, a daily newspaper published from Jammu, had quoted Indian defence sources as saying that the 313 Brigade had been formed by the Inter-Services Intelligence (ISI) a few days earlier. They claimed to have killed its leader within a few days of its formation and infiltration into J&K.
Thereafter, from to time, there were references to the activities of the 313 Brigade in the Surankote area of J & K. In October 2004, a Rashtriya Rifles unit captured one Sabzar Ahmed, a resident of the Surankote area, who was described as a member of the 313 Brigade.
On March 17, 2006, The Nation, the Pakistani daily, had carried a report on a letter jointly written to Pervez Musharraf by the members of the United Jihad Council of Kashmir protesting against his government succumbing to pressure from the George Bush administration to discontinue support to the Kashmir-related jihadi organisations. Among those who had signed the letter was one Munir Ahmed of the 313 Brigade.
In April 2006, the US State Department issued the 2006 "Country Reports on Terrorism," which listed a number of designated "foreign terrorist organizations" and also listed "other selected terrorist groups also deemed to be of relevance to the global war on terrorism." The HUJI was listed in the latter category. The report noted the group's "links to al Qaeda," and that the "HUJI's operations in Kashmir were led by Commander Ilyas Kashmiri, a former commander in the Afghan jihad, .... who was arrested in October2005 on charges of attacks against President Musharraf in 2003."
Reports in the Pakistani media indicated that Ilyas Kashmiri, who headed the 313 Brigade of the HUJI in J&K, was released by the Pakistani authorities on the intervention of Syed Salahuddin and had shifted from Pakistan-Occupied Kashmir (POK), where he was previously based, to the Waziristan area of the Federally-Administered Tribal Areas (FATA).
A second organisation also known as the 313 Brigade is Pakistan-centric and is the fighting arm of the International Islamic Front for Jihad Against the Crusaders and the Jewish People formed by Osama bin Laden in 1998 in association with a number of terrorist organisations of Pakistan, Bangladesh, Uzbekistan and other countries. It came into existence after the US invasion of Iraq in 2003. It looks upon the US and Israel as its main enemies. It is strongly against the Pakistan Govt, its Army and the ISI because of their alleged co-operation with the US in Afghanistan.
While the Kashmir-centric 313 Brigade claims responsibility for its actions in Jammu & Kashmir, the Pakistan-centric 313 Brigade does not admit its operations in Pakistan. Till 2007, the responsibility for the attacks on Pakistani army and ISI officers was claimed by organisations with names such as the Islambouli Brigade, the Jundullah etc. After the raid by the Special Services Group (SSG) of the Pakistan Army into the Lal Masjid of Islamabad in July,2007, the responsibility for many of the attacks on military establishments and personnel has been claimed by the Tehrik-e-Taliban Pakistan (TTP).
Among the terrorist attacks in Pakistani territory in which the Pakistan-centric 313 Brigade was suspected were: