Soviet Foreign Ministry spokesman Gennady I. Gerasimov told reporters in Moscow that tanks and troops had been sent to Kirovabad, Baku and a third Azerbaijani city, Nakhivechan, to restore order.
It said "measures are being taken to maintain legality and safety of citizens" in Kirovabad and Nakhichevan.
A Communist Party official said "small groups of hooligan youth" demonstrated Monday in Kirovabad, near the border with Soviet Armenia.
Soldiers in tanks and personnel carriers continued to patrol Kirovabad even though there had been no protests for the past two days, Sadykhov said.
Four soldiers were killed protecting Armenian residents of the Azerbaijani city of Kirovabad, and soldiers shot and killed three civilians there for violating curfew.
Musa Mamedov, chief of the information department of the Azerbaijani Foreign Ministry, said Thursday night that reports from the city of Kirovabad were sketchy but that several people had been killed in the latest outburst.
A curfew has been imposed and Soviet tanks and troops sent in recent days to curb unrest in Kirovabad, Baku and Nakhivechan.
Mamedov, the republic's Foreign Ministry spokesman, said mobs in Kirovabad and Nakhichevan attacked local government headquarters and thetroops defending the buildings.