OAKLAND -- Two boys, ages 14 and 15, have been arrested as suspects in at least a half-dozen robberies and carjackings over a two-day period this week, police said Friday.

A 15-year-old girl was detained but released pending further investigation and a 14-year-old boy is being sought, police said,

Police said the 15-year-old boy who was arrested admitted his involvement in the spree, saying he and the others needed money. They face multiple counts of robbery and carjacking, authorities said.

The crimes happened between 2:15 p.m. Tuesday and 3:10 p.m. Wednesday in different parts of Oakland, including the Dimond and Fruitvale districts.

Officer Hector Jimenez said the suspects would steal cars to look for victims. The suspects would strong-arm the victims, and if that did not work, one of them would threaten the victim with what turned out to be a replica pistol.

The suspects were arrested Wednesday a few hours after a robbery at 3:10 p.m. in the 2700 block of Coolidge Avenue, where a 20-year-old woman was thrown to the ground and had her purse and cellphone taken by robbers who fled in a black SUV. The woman was treated at a hospital for her injuries and the 2014 Dodge SUV, which was carjacked earlier, was recovered later in the 900 block of Bayview Avenue.

The 14-year-old suspect who is still being sought left the other three on Bayview, police said. They then stole a Honda that was stopped later by police in the area of 96th Avenue and Sunnyside Street. Three other boys, ages 14 and 15, who had been picked up the other three were detained but later released.

The SUV was taken at gunpoint from a 52-year-old woman about 9 a.m. Wednesday at a Safeway store parking lot, 3550 Fruitvale Ave, police said.

Victims in the other robberies and a carjacking were men and women ranging in age from 31 to 55. They occurred on 39th Avenue and Mera Street, the 200 and 3000 blocks of MacArthur Boulevard and the 3600 block of Kingsley Street.

Police believe the two boys arrested could be responsible for more robberies in Oakland and other cities and are asking ask that anyone with information contact investigators at 510-238-3326.