The assault is one of two reported incidents involving a man approaching teenage girls in Horsforth on Saturday afternoon.
Police said it was not yet clear what the motive had been but patrols had been stepped up in the area.
The 16-year-old was in Town Street, near to its junction with Kerry Street, when she was approached by the man shortly after 5.30pm.
He grabbed her shoulder initially, then grabbed her hair when she pulled away from him.
The suspect ran off when the girl screamed and two women nearby went to her aid.
Officers later received a report of another incident in Hall Lane at about 5.45pm.
A similarly-described man had approached a 15-year-old girl and asked her for a hug .
The girl refused and the man called her a name as he walked off.
Detective Inspector Phil Jackson, of Leeds District CID, said: "We are keeping an open mind as to whether these two incidents are linked but there are real similarities.
"These incidents are obviously a cause for concern, however nothing was said or done that suggested a clear sexual motive or robbery and we are treating the main incident in Town Street as a physical assault.
"We fully appreciate that these incidents will cause concern in the local community and neighbourhood officers have been made aware and will be conducting increased patrols of the area to provide reassurance."
The suspect was described as white, slim, and aged in his mid twenties with short, messy, dark blonde hair.
He was wearing a blue checked long sleeve shirt and black skinny jeans.
Det Insp Jackson said: "We would like to hear from anyone who witnessed either incident or who saw a man fitting the description in the area around the time. We are particularly keen to trace the two women who went to the victim's aid in Town Street."
Anyone with information is asked to contact Leeds District CID via 101, quoting crime number 13170032688.
Information can also be passed on to independent charity Crimestoppers anonymously on 0800 555 111.