The Directorate for Inter-Services Intelligence (more commonly known as just the Inter-Services Intelligence or simply by its initials ISI) is the premier military-operated intelligence service of Pakistan, operationally responsible for providing critical national security and intelligence assessment to the Government of Pakistan. The ISI is the largest of the three intelligence services of Pakistan, the others being the Intelligence Bureau (IB) and Military Intelligence (MI). Previously in the 20th century, the ISI's work and activities have included the support of the Afghan mujahideen in then-communist Afghanistan against the Soviet Union in their war against the mujahideen (in conjunction with the Central Intelligence Agency) and later provided strategic and intelligence support to the Afghan Taliban against the Northern Alliance in the civil war in Afghanistan in the 1990s.