Authorities charged three teens -- two as adults -- for attempting to rob a woman near White Flint Mall in Rockville on New Year's Day.

A 56-year-old woman who had just left the mall was walking along the 5800 block of Nicholson Lane at 5:48 p.m. Monday when she was approached by the teens, who demanded cash, according to Montgomery County police.

The woman began to scream when one of the suspects punched her in the head, and they fled toward the White Flint Metro station, according to police.

An off-duty Montgomery County police officer followed them to the Metro station, where other officers responded and arrested the teens.

District residents Tywone Omid Sommers, 16, and Jalonte Malki Cole, 17, were each charged as adults with armed robbery, second-degree assault and conspiracy to commit both. Cole was also charged with concealing a dangerous weapon -- officers found a BB pistol in his waistband when he was arrested Monday, police said.

The 15-year-old teen, a Glen Arden resident, was charged as a juvenile with armed robbery and second-degree assault, as well as conspiracy to commit both.

Cole was being held Thursday pending a $50,000 bond, while Sommers was released on bond Tuesday, according to police.