OAKLAND (CBS SF) -- Oakland police are investigating two armed robberies reported Friday in the city.

In the first, the victim was walking her dog at about 3:50 p.m. in the 400 block of Jean Street when a suspect with a handgun approached her and robbed her of her cellphone, police said.

The suspect was described as a black man in his 20s, 5 feet 9 inches tall, wearing a black hooded sweatshirt and carrying a gray semi-automatic handgun.

Then at 8:55 p.m., a victim sitting on a bench in the 100 block of Grand Avenue was robbed by two suspects, one of whom had a gun, police said.

The first suspect was described as a black man in his mid 20s, 5 feet 7 inches tall and 140 pounds, wearing a black hooded sweatshirt and carrying a black semi-automatic handgun.

The second suspect was reportedly a black man in his 20s, 6 feet tall and 180 pounds, wearing a black T-shirt and blue jeans.

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