Helicopters are circling over Oxford as emergency services attended calls to a man in the river.
Two emergency helicopters were overhead at around 2.30pm after the fire service was initially called out at 1.23pm.
A spokesman for Oxfordshire Fire and Rescue Service said four fire engines and a fire and rescue boat were sent in response.
READ MORE: Oxford river search as air ambulance called to incident
Police cars were also seen racing down Botley Road earlier in response to the incident.
The footpath and bridge in Osney Lock has been closed off while emergency services conduct the searches.
The fire and rescue confirmed it is actively searching for a male suspected to be in the river.
Boats have been deployed on the river while police officers are also standing by the water on duty.
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