A huge emergency operation has been launched after a man was reportedly seen in the River Trent.
Police, fire and ambulance crews have descended on the Victoria Embankment in Nottinghamshire.
Neighbour Nicola Rose, told Nottinghamshire Live : "There are nine fire engines, four ambulances and two police cars.
"There is an under water search team and more sirens are coming.
"There are loads of flashing lights and my daughter has just seen the air ambulance landing."
A spokesman for Nottinghamshire Police said: "Police can confirm they are in attendance after a reports for concerns for a mans safety after they were seen entering the water at about 1.15pm."
Witness Keith Windel saw two men go into water.
A helicopter is assisting boat teams with the search.
The 62-year-old of Cotgrave, said: “Being a Nottingham lad you know what this river is like.
“One reached the other side but the other started to struggle and he went under a couple of times.
“We just came down here for a quiet walk.”
Gary Wardel, 53, of Clifton, was doing his regular 10 mile walk when he saw two men going for a swim.
But he says he only saw one person emerge from the water.
He said: “There was a boat trying to help him and other two men jumped in to help. I just wanted to jump in.
“No one knows how strong the current is. I used to swim in it when I was younger but I wouldn’t now. It’s a horrible thing to see. I couldn’t believe it at first, I thought he was messing around.”
A police statement read: "Nottinghamshire Police are currently in attendance at the Victoria Embankment, as they respond to reports of concerns for the safety of a man who was seen getting into difficulty after entering the River Trent just before 1.15pm today.
