At least 21 fires were set across an area of about four square miles, Belmar said.

Neither he nor Johnson would say that the Missouri National Guard had not been adequately used Monday — a common charge on Tuesday — but Belmar said he "welcomed" the additional force that Gov. Jay Nixon has promised for Tuesday night.

The guard is providing 2,200 soldiers.

Belmar and Johnson spoke during a press conference about 4:30 p.m. Tuesday at the Buzz Westfall shopping center (formerly Northland) on West Florissant Avenue, just south of the strip that was the scene of most of the protests in August. Several fires were set along West Florissant late Monday and early Tuesday, and other fires burned along Florissant Road on both sides of Ferguson's downtown.

Johnson said the rioting "was not fair to this community. We have to make sure that this stops."