The Soviet Union reported today that a major oil and natural gas center was shaken Sunday by rioting apparently related to recent nationalist unrest.

The demonstrations appear to be the most serious case of nationalist unrest in the Soviet Union in many years.

In previous comments, Mr. Gorbachev took a much harder line on nationalist unrest in the south.

The disturbances, which appear to have subsided, were among the most serious forms of nationalist unrest in the Soviet Union since the early 1920's.

The disturbances involve some of the most serious nationalist unrest in the Soviet Union since the 1920's.

Tito's death on 4 May 1980 ushered in a long period of political instability, worsened by growing economic crisis and nationalist unrest.

Government reports suggested that major Armenian nationalist disturbances constituted the most serious case of nationalist unrest in many years.

The disturbances have been among the most serious outbreaks of nationalist unrest since consolidation of the Soviet Union in the early 1920's.

Last week the Government confirmed that two people were killed and several dozen hurt during nationalist unrest in the two republics.

The Soviet Union is increasingly fraught with nationalist and ethnic unrest, and its economy cannot fulfill the basic needs of the people.