<P> On February 12--14, 1990, anti-government riots took place in Tajikistan's capital, Dushanbe, as tensions rose between nationalist Tajiks and ethnic Armenian refugees, after the Sumgait pogrom and anti-Armenian riots in Azerbaijan in 1988 . During these riots, demonstrations sponsored by the nationalist Rastokhez movement turned violent . Radical economical and political reforms were demanded by the protesters which in turned torched government buildings; shops and other businesses were attacked and looted. 26 people were killed and 565 people were injured . </P> <P> In June 1990, the city of Osh and its environs experienced bloody ethnic clashes between ethnic Kirghiz nationalist group Osh Aymaghi and Uzbek nationalist group Adolat over the land of a former collective farm . There were about 1,200 casualties, including over 300 dead and 462 seriously injured . The riots broke out over the division of land resources in and around the city . </P> <P> On January 14, 1991, Nikolai Ryzhkov resigned from his post as Chairman of the Council of Ministers, or premier of the Soviet Union, and was succeeded by Valentin Pavlov in the newly established post of Prime Minister of the Soviet Union . </P> <P> On March 17, 1991, in a Union - wide referendum 76.4 percent of voters endorsed retention of a reformed Soviet Union . The Baltic republics, Armenia, Georgia, and Moldova boycotted the referendum as well as Checheno - Ingushetia (an autonomous republic within Russia that had a strong desire for independence, and by now referred to itself as Ichkeria). In each of the other nine republics, a majority of the voters supported the retention of a reformed Soviet Union . </P>

Who was the soviet premier when the soviet union collapsed in 1991 formally ending the cold war