In each case, someone pulled up to pedestrians in a car and demanded money before fleeing, police said. View Full Caption DNAinfo/Kelly Bauer

CHICAGO — Two similar robbery attempts were reported a week apart in Sauganash and North Park this month, according to a police alert issued Monday.

In each incident, a group of men in a gray car pulled up to pedestrians and demanded money, then drove away without taking anything, police said.

In the second incident, the men "implied that they were armed," police said.

The first attempted robbery was reported at 5:45 a.m. in the 6100 block of North Keating Avenue, police said. Suspects in that incident were described as three black men and one Hispanic man, driving a gray or silver car, "possibly a Toyota Corrola."

The second incident was reported just after midnight on Sunday morning in the 6100 block of North Central Park Avenue, police said. Those suspects were described as three Hispanic men inside a gray car, "possibly a Lexus."

Anyone with information on the suspects or the incidents is asked to call detectives at 312-744-8263.