One man, in his fifties, was airlifted to Aberdeen Royal Infirmary with life-threatening injuries after the accident at the Granite City Rally in Durris Forest yesterday.
Two other men sustained serious injuries and a fourth suffered minor injuries as a result of the crash around 11.20am yesterday.
A Nissan Micra taking part in the event initially crashed off the forest track. It was followed by a Peugeot 205 that came off the track at the same spot several minutes later, ploughing into spectators who were lining both sides of the route, according to the Aberdeen and District Motor Club.
Course clerk Ian Shiells said last night: “Obviously this is sad incident, and our thoughts are with the injured spectators.”
The 44-mile rally involves more than 100 crews starting from the Thainstone Agricultural Centre, near Inverurie. The event was cancelled after the incident, which occurred in the opening stages.
Grampian Police have urged any witnesses who have not yet spoken to the police to get in touch.