Emergency services are searching for a person in the river at Peterborough.
Cambridgeshire Police and Cambridgeshire Fire and Rescue Services are currently at near Stanground Lock near Wessex Close searching for the person.
Crews were called at 3.10pm today after receiving reports of a person in the river.
The Cambridgeshire police helicopter has also been called to search the river from above.
A police spokesman said they had been alerted to the incident by a member of the public.