Two girls aged 11 and 14 have been assaulted, one of them sexually, by a man in Bath.
The attack happened on a track between Ringswell Gardens and the Kennet and Avon Canal at about 1600 BST on Tuesday.
He grabbed the older girl by the throat, pushed her into some bushes and sexually assaulted her.
Avon and Somerset Police said the younger girl tried to pull him away, but he pushed her over.
The girls' screams were heard by two fishermen who ran to help and the attacker walked away.
The girls were said to be severely shaken and upset, but not physically injured.
Officers said the girls had been aware of a man behind them who then overtook them, slowed down as he reached Grosvenor Bridge, then turned round and attacked them.
Det Insp Charlotte Tucker, of Bath CID, said: "This was a serious assault on two young girls in the middle of the afternoon on a well-used path.
"We are extremely keen to find the man responsible as soon as possible."
The attacker is described as white, 25 to 30 years old and about 5ft 10in tall.
He had very short blond or fair hair and was wearing a blue, pink and grey-hooped rugby-style polo shirt with long sleeves, blue jeans and trainers.
Police are carrying out forensic tests, and officers are at the scene providing reassurance and speaking to possible witnesses.