The Detroit Free Press said the numbers released by Mayor Dave Bing's office did not include reports from the pre-dawn hours of Sunday.
The three days before Halloween have been an odd time for Detroit for many years as residents used the occasion to set fires in trash bins and vacant homes. The "Devil's Night" trend peaked in 1984 when more than 800 fires were reported.
The period was re-christened "Angel's Night" by the city five years ago and now includes a stepped up law-enforcement presence and volunteer patrols on the streets
Bing's office told The Detroit News that Saturday's alarms were fairly in line with a normal day for the city's fire department.
"So far the numbers are encouraging, but we don't want to count our chickens before they're hatched," Bing said Saturday during a visit to a fire station.