Congo's democratic progress was derailed in 1997 when Lissouba and Sassou started to fight for power in the civil war. As presidential elections scheduled for July 1997 approached, tensions between the Lissouba and Sassou camps mounted. On June 5, President Lissouba's government forces surrounded Sassou's compound in Brazzaville and Sassou ordered members of his private militia (known as "Cobras") to resist. Thus began a four-month conflict that destroyed or damaged much of Brazzaville and caused tens of thousands of civilian deaths. In early October, the Angolan socialist régime began an invasion of Congo to install Sassou in power. In mid-October, the Lissouba government fell. Soon thereafter, Sassou declared himself president.

Which two figures clashed over leadership of the Congo in 1997?