The greatest threat to Mahkamov's power came during the February 1990 Dushanbe riots that rocked the capital. Tajik youths clashed with non-Tajiks and battles were fought in the streets of Dushanbe between rioters and police and soldiers, resulting in dozens of deaths. Mahkamov oversaw a crackdown on Islamic fundamentalists and a lengthy curfew was put in place. He served as Chairman of the Presidium of the Supreme Soviet (head of state) from 12 April to 30 November 1990. As part of the political reforms that Gorbachev was instituting the Supreme Soviet of Tajikistan appointed Mahkamov the first President of Tajikistan on 30 November 1990. Mahkamov's fall from power came in August 1991 when he supported the failed August Coup by hardliners in Moscow. Protestors took to the streets and demanded Mahkamov's ouster from power and on August 31, 1991 he resigned his positions as President and First Secretary. Mahkamov then retired from politics and sat on the sidelines during the ensuing political instability and Civil War in Tajikistan.