A girl is fighting for her life in hospital after three of her family members died after getting into trouble in the water off Shoreham-by-Sea.
Emergency services were called on Tuesday afternoon following reports of four people in difficulty in the open water, Sussex Police have said.
Several ambulances and two air ambulances were seen near the RNLI station in Shoreham-by-Sea, West Sussex, on Tuesday afternoon.
It is thought the four family members went into the sea for a swim.
Sussex Police confirmed on Tuesday night that a man, a woman and a teenage girl had died, while a younger girl from the family was in a critical condition in hospital.
Officers have not named the victims but said their next of kin had been informed and were being supported by specialist officers.
Joss Loader, who lives nearby and represents Shoreham Beach Residents’ Association on Adur District Council, said: “There’s just a really strong sense of shock, obviously people are really concerned for the young girl.
“A small tightly knight community with a very deep sense of shock and that sense of disbelief you get after a tragedy because it has come out of nowhere.”
Shoreham Beach is a spit of land with water on three sides from the River Adur, the estuary and the sea, and Ms Loader said the “tragic events” happened in the estuary.
“It’s school holidays and we have had a wonderful summer so the beaches have been packed with families,” she said.
“The weather was quite calm, not as hot as recent days but it was a perfectly normal day.
“People swim from those beaches even in the winter, generally it is considered as safe as the sea can be. You wouldn’t be swimming there and think you were taking a risk.”
Speaking to reporters, Chief Superintendent James Collis said: “Around 2:40 pm this afternoon, emergency services were called to reports of four people in difficulty in the water close to Shoreham Fort.
“Sussex Police supported His Majesty’s Coast Guard and the RNLI as all four people were brought to shore.
“Tragically, despite the best efforts of paramedics, three people – a man, a woman, and a teenage girl – were sadly confirmed deceased.
“A younger girl has been taken to hospital and is in critical condition. We can confirm all four people were from the same family, and their next of kin have been informed.”
The A259 Brighton Road was blocked in both directions from New Road to Kingston Lane because of the incident.
A resident, who asked to remain anonymous, told The Telegraph: “I heard from friends in the coastguard that it was a family who had been living in tents by the harbour front.
“They were camping just between the harbour arm and the fort. They have been there for a couple weeks, I’ve walked my dog past them. People don’t usually camp there.”
Alan Facer, a fisherman from Hove, told the newspaper: “The wind earlier was south-westerly so usually the waves pick up quite a bit.
“At 3pm, the tide would have been quite high.
“I was thinking the other day that someone is going to get hurt around here.”
Shoreham-by-sea is a coastal town outside of Brighton, and is a popular spot for families and day-trippers heading to the beach.
Water sports are popular from its shingle beach, including paddleboarding and kitesurfing, while parts of the harbour and port areas are used for industrial purposes.
An RNLI spokesman said: “Shoreham RNLI were tasked by HM Coastguard at approximately 3pm on Tuesday 18 August.”
At the scene, an ambulance could be seen leaving under a police escort with blue lights flashing.
An HM Coastguard spokesperson added: “HM Coastguard responded to an incident reported at Shoreham at about 2.45pm on 18 August.
“An HM Coastguard helicopter was sent as well as Littlehampton, Shoreham and Newhaven Coastguard Rescue Teams, and an RNLI lifeboat from Shoreham.
“Sussex Police and South East Coast Ambulance Service also attended.”
The South East Coast Ambulance Service also said they were responding to reports that four people needed medical attention after getting into difficulty in the water near Shoreham Harbour.
“We were called shortly after 3pm and have a number of ambulance resources at the scene,” a spokesperson said.
“We have no further information to share at this time but will provide updates as soon as possible.”
East Worthing and Shoreham MP Tom Rutland said in a statement on Facebook: “I am deeply saddened by the tragic news that three people have died following an incident in the water near Shoreham Fort this afternoon.
“I spoke earlier with Sussex Police and Shoreham RNLI and have been briefed on the response by the emergency services.
“My thoughts are with the family and friends of those who have lost their lives, and I know the whole community here in Shoreham will be hoping and praying for the recovery of the young girl receiving medical treatment in hospital.”