The term "strategic depth" has been used in reference to Pakistan's utilization and contact with Afghanistan following the neighboring country's Soviet intervention, to prevent encirclement from a hostile India and a USSR-supported Afghanistan. Some sources state that the policy to control Afghanistan was formulated by NDU professor, General Mirza Aslam Beg, and an Indian source claims this was continued as an active policy by the Pakistan Armed Forces until the policy was "de jure abolished in 1998 and de facto abolished in 2001", period when General Pervez Musharraf was the Chairman joint chiefs.