A Palestinian couple and their teenage daughter who died after getting into difficulty in the sea had travelled from their home in London for a visit to Shoreham, police have said.
Hassan El-Khawas, 55, his partner Zeina Alayn, 37, and their 14-year-old daughter, Sara El-Khawas, are believed to have entered the water for a swim with another young female family member near Shoreham Fort in Shoreham-by-Sea, West Sussex.
The fourth family member remains in hospital in a critical condition.
A major emergency response, involving police, paramedics and coastguard crews, was launched after reports of people in difficulty in the water on Tuesday afternoon.
Sussex Police said it is believed all four entered the sea to swim, although the exact circumstances surrounding the tragedy have yet to be established.
Officers said there is currently nothing to suggest any third-party involvement, and an investigation into the deaths remains ongoing.
Sources have also said there is no evidence at this stage to suggest a fishing net was involved in the incident.
Adnan Hmidan, chairman of the Palestinian Forum in Britain, said two other children from the family were on the shore at the time and are now being cared for by their uncle.
Mr Hmidan said the girl who survived and remains critically ill in hospital is the younger daughter of Mr El-Khawas and Ms Alayn.
Mr Hmidan says the family are British citizens of Palestinian origin and had roots in the Rashidieh refugee camp in Lebanon.
"Like many Palestinian families, members of their extended family have lived in Britain for many years and have built a strong and close-knit community here," he said.
"Our thoughts and prayers are with the entire family, particularly the children, who are facing an unimaginable loss."
Rashidieh Camp is on the Mediterranean coast in southern Lebanon and is one of the most populous Palestinian refugee camps in the country.
In a statement on Facebook, the embassy said it was “closely monitoring the incident”.
It added: “As the embassy extends its deepest condolences and sympathy to the victims’ family, their loved ones, and members of the Palestinian community in the United Kingdom in this painful affliction, it wishes the injured girl a speedy recovery.”
Prime Minister Andy Burnham warned of the dangers of open water swimming after the incident, which he described as “a terrible family tragedy”.
He said: “The thing I can say today – and there is still, I think, a further heatwave to come in this summer period – it is just to remind people about the dangers of open water swimming.
“The coldness, even when it feels hot outside, it can shock people and that can cause the difficulties. So people just need to remember that at all times.
“I do need to praise the emergency services who I know were on scene very quickly yesterday. They’ve had a busy summer but they were there and we thank them.”
Video footage showed a number of emergency services searching an area of water near to an arm of the harbour where the River Adur meets the sea.
Chief Superintendent James Collis said: “The events of Tuesday afternoon are a heartbreaking tragedy which has devastated a family and their friends and had a profound impact on the Shoreham community.
“The thoughts of all at Sussex Police remain with the family’s loved ones as we work with our partners, including HM Coroner, to understand exactly how this incident occurred.
“The emergency response was significant, and I would like to thank all of the first responders for their determined attempts to save all four people, as well as the wider public for their patience during the incident.
“We will release further updates as soon as we are able, but we ask the family are given the privacy they deserve at this incredibly difficult time.”
The force said it will prepare a file for the coroner ahead of any inquest.
