 The Soviet Union, that had been supporting Afghanistan economically and militarily since 1919 (see Soviet–Afghan War#Soviet–Afghan relations) and early 1979 had sent hundreds of military and civilian advisers into Afghanistan after a request from President Nur Muhammad Taraki, in December 1979 invaded Afghanistan with its 40th Army, around 75,000 strong, killed the new President Hafizullah Amin, and installed Soviet loyalist Babrak Karmal as President of a Soviet-organised and –backed PDPA-regime.In spite of a UN General Assembly resolution condemning the 1979 USSR invasion and the Organisation of Islamic Cooperation demanding immediate Soviet withdrawal, the Russians stayed until early 1989.They managed to take control of major cities and strategic installations, thus acerbating nationalistic feelings among rebels who drew Soviet troops into war with urban uprisings and tribal armies.