The area of the River Tees where the accident happened
A man has died after falling through thick ice on the River Tees in Stockton while trying to rescue his two dogs.
The man, who was in his mid-50s, was attempting to reach the animals which had strayed on to the ice close to the town's Infinity Bridge, police said.
The coastguard, the Cleveland Police fire boat and a police helicopter were involved in a rescue operation.
Attempts were made to revive him at the scene but he was pronounced dead at Middlesbrough's James Cook Hospital.
Police have urged people to stay away from frozen water.
A member of the public alerted the emergency services at about 1300 GMT.
A spokesman for Humber Coastguard said the man fell into the river about 50m (164ft) from the northern bank of the river.
He said: "The ambulance service was already on their way and Redcar Coastguard Rescue Team were immediately called out.
"As the incident was above the barrage no lifeboat could be utilised in that location so the fire service attended using their fire boat.
"Initially when the rescue services arrived on scene he could not be seen but eventually, with the aid of a police helicopter, he was located and pulled from the water and rushed to hospital.
"Immediate resuscitation was given to him and continued as he was loaded on board the ambulance."
The dogs have not been found.
The spokesman added: "We are advising all dog walkers to be very, very careful in these treacherous conditions."
A large area of the River Tees has been frozen for several days.