The incident happened as the 47-year-old victim was crossing a footbridge over the A58 near the gas tower at the Armley Gyratory at about 5.30pm yesterday. (Nov 8)
She saw a man walking towards her before he exposed himself and made a number of comments.
The woman kept walking but the man then grabbed her from behind and sexually assaulted her.
He stopped the attack and walked off towards the city centre when his victim hit out at him.
The man is described as white, aged about 30, 5ft 7in tall and stocky.
He had a pale complexion and thick dark hair with a fringe and was wearing a parka type coat and dark trousers.
Det Insp Phil Jackson, of Leeds District CID, said: “This was obviously a really distressing experience for the victim and we are carrying out extensive enquiries to trace this man.
“This is a popular pedestrian route from the city centre and we would like to hear from anyone who was around at the time and saw someone fitting the suspect’s description in the area.
“The victim reported shouting a warning to two other women that she saw approach the footbridge from the Leeds side after the incident and we are keen to trace those woman as potential witnesses.
“Officers from the local neighbourhood policing teams that cover the area are mounting increased patrols to reassure the community and deter any further offences.
“Our advice to people remains the same as at any other time, in that we would encourage them to always consider their personal safety and be conscious of their surroundings when out and about.”
Anyone with information is asked to ring Leeds District CID on West Yorkshire Police’s 101 number, quoting crime reference 13160559100.