Gorbachev refused to make any changes to the status of Nagorno Karabakh, which remained part of Azerbaijan. He instead sacked the Communist Party Leaders in both Republics – on May 21, 1988, Kamran Baghirov was replaced by Abdulrahman Vezirov as First Secretary of the Azerbaijan Communist Party. From July 23 to September 1988, a group of Azerbaijani intellectuals began working for a new organization called the Popular Front of Azerbaijan, loosely based on the Estonian Popular Front. On September 17, when gun battles broke out between the Armenians and Azerbaijanis near Stepanakert, two soldiers were killed and more than two dozen injured. This led to almost tit-for-tat ethnic polarization in Nagorno-Karabakh's two main towns: The Azerbaijani minority was expelled from Stepanakert, and the Armenian minority was expelled from Shusha. On November 17, 1988, in response to the exodus of tens of thousands of Azerbaijanis from Armenia, a series of mass demonstrations began in Baku's Lenin Square, lasting 18 days and attracting half a million demonstrators. On December 5, 1988, the Soviet militia finally moved in, cleared the square by force, and imposed a curfew that lasted ten months.