Police vehicles were stoned in Ujjain district on Monday night ahead of Madhya Pradesh Chief Minister Shivraj Singh Chouhan's 'Jan Ashirwad Yatra', an official said.
The incident took place on the Mahidpur-Jaora road, an hour before Chouhan's convoy was to pass along the same route, a police official said.
"Some people hiding in the darkness attacked police vehicles. Three vehicles were damaged...some police personnel were also injured," said Taal Police Station's in-charge Vinod Baghel.
Chouhan is on a state-wide tour ahead of the coming Assembly elections.
State Congress president Kamal Nath on Tuesday condemned the attack, but also said it showed people's anger.
"We condemn the incident. This is people's anger against the BJP rule. The government has not fulfilled its promises. Youths are not getting jobs," Nath told reporters here.