 However, with an aggressive armed opposition, internal difficulties such as a failed coup attempt by the Khalq faction in 1990 and the dissolution of the Soviet Union in 1991, the Najibullah government collapsed in April 1992.Geographically, the DRA was bordered by Pakistan in the south and east; Iran in the west; the Soviet Union (via the Turkmen, Uzbek, and Tajik SSRs) in the north; and China in the far northeast covering of its territory.Mohammad Daoud Khan, the President of the Republic of Afghanistan from 1973 to 1978, was ousted during the Saur Revolution (April Revolution) following the death of Mir Akbar Khyber, a Parchamite politician from the People's Democratic Party of Afghanistan (PDPA) who died under mysterious circumstances.