Haiti President Rene Preval says authorities will demolish unsafe buildings and improve urban planning following a school collapse that killed nearly 100 people.

Radio Metropole is reporting that Preval will hold three days of meetings with mayors next week about widespread, lawless construction in fast-growing slums.

Preval spoke Wednesday at a presidential palace tribute to victims of the Nov. 7 collapse of the K-12 College La Promesse.

The mayor of Port-au-Prince has estimated that 60 percent of the city’s buildings are unsafe. Many are the homes, schools and churches of families who fled rural poverty to shantytowns.