Emergency services are searching part of the River Thames for a boy who was seen getting into difficulty in the water.
Thames Valley Police said on Twitter that officers were at the river between Bourne End, Buckinghamshire, and Cookham, Berkshire, on Monday afternoon following a report of a fear for welfare incident.
The force received a report at 3pm that a teenage boy had entered the water and got into difficulty.
He was not seen to leave the water, prompting a search by police and the fire service.
Thames Valley Police said there will be a police presence in the area while the search takes place.
It comes after officers from the same force were called to Boulters Lock, at the River Thames in Maidenhead, earlier on Monday, after a report of a woman’s body in the river at 7.15am.
The force said the woman’s death is being treated as unexplained and that formal identification has yet to take place, with officers working to establish the circumstances and to identify a next of kin.
Boulters Lock and Cookham Lock are both closed and police are asking that members of the public avoid the area.
Elsewhere, a two-year-old boy is in a critical condition in hospital after being pulled from a lake in Hampshire by emergency services on Sunday.
Hampshire Constabulary are appealing for witnesses after the boy was found unresponsive in water at Swanwick Lake, a nature reserve near Fareham, on Sunday.
The force said that an 18-year-old man from Southampton, who officers said is known to the boy, has been arrested in connection with the incident.
The child was taken to Southampton General Hospital where he remains in a critical but stable condition, police added.
Officers are appealing for information and would like to hear from anyone who was in the area between 7.45pm and 8.30pm.
Detective Inspector Toby Elcock said: “We know this incident will come as a shock to the local community, but we ask people to please not speculate as we follow up all lines of inquiry to establish how the boy came to be in the water.
“We are keeping an open mind as to what has happened, and we are keen to speak to anyone in the area to help us build up a picture of the circumstances.
“If you were in the area at this time, please call us. Any information, no matter how small, could prove significant, so please do get in touch.”
People are asked to contact officers on 101 quoting 44210210811 or through charity Crimestoppers anonymously on 0800 555 111.