Minneapolis detectives are investigating a string of armed robberies early Monday morning to determine whether they're connected.

All six took place in a span of 90 minutes in neighborhoods south of downtown Minneapolis, police said. In each case, at least one of the suspects was armed with a gun. Victims in each case gave similar descriptions of the suspects.

No one had been arrested as of Monday night.

The first episode happened at 5:43 a.m. in the 3800 block of S. 25th Avenue when two young men carjacked two SUVs — a black Kia Sedona and a dark gray Volkswagen Tiguan — and drove off, according to a police summary.

About 45 minutes later, someone in the 4200 block of Blaisdell Avenue was robbed at gunpoint by a gunman who fled in a red SUV.

A third robbery happened around 6:41 a.m. in the 4300 block of S. Pleasant Avenue. Police said that about 10 minutes later, officers encountered a victim near S. 49th and Columbus avenues who was reportedly robbed by two men.

Another carjacking was reported about 6:58 a.m. in the 5300 block of Columbus — four blocks north of the last robbery. In the most recent robbery, a young male suspect stole a laptop, a tote bag and a bank card, before fleeing in a black or gray SUV, according to police. The incident happened about 7:14 a.m. in the 4300 block of S. 13th Avenue.

Staff writer Paul Walsh contributed to this report.

Libor Jany • 612-673-4064 Twitter: @StribJany