A young girl was approached by a man who made suggestive comments in the second incident of its kind in Oxfordshire this month.
The 11-year-old victim tried to hit the man when he made the lewd comments as she walked through Southmoor, near Abingdon.
The attack happened at 5.40pm on Thursday but police only released details to the public yesterday.
Police have not ruled out a link with another sex attack on a 10-year-old girl, in Bampton, near Witney, earlier this month.
Police spokesman Kate Smith said that in this latest incident, the girl was walking along Stonehill Lane, Southmoor, when she was approached by a man near a bus stop.
The girl, who was in her school uniform, tried to strike the man, who ran off down Sandy Lane.
The man is white, 5ft 7in tall and in his late 20s to early 30s. He has dark brown hair and was wearing a white T-shirt and knee length blue shorts.
The sexual assault in Bampton, near Witney happened at 5pm on Wednesday, September 6.
As reported in the Oxford Mail, the victim was walking home when a balding, middle-aged man wearing running gear groped her.
Police failed to release details of that attack until five days later, when they made an appeal for witnesses.
The attacker is described as a white man wearing a white T-shirt, blue shorts and trainers.
After the assault, he fled towards the village centre shops. The young girl ran home and called the police, who searched the area but made no arrests.
Miss Smith said: "We will look into the possibility that they could be linked but there is no evidence to suggest that they are at this time."
When asked why details about these incidents were not released sooner, Miss Smith said: "Police release information to the media when appropriate to an investigation."
If you have any information, call police on 08458 505505 or Crimestoppers on 0800 555111.
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