Police say they believe they have identified the three women who died in the sea off Brighton beach following "extensive" inquiries.
Sussex Police said emergency teams were first called on Wednesday at about 05:45 BST to a report of a single person in the water near Black Rock car park in Madeira Drive, which runs along the beachfront.
On arrival, two more bodies were recovered from the sea nearby.
Brighton & Hove City Council leader Bella Sankey said it was "the most devastating news" the city had received "for a very long time".
"I can't think of anything more tragic or more horrendous really," she told BBC Radio Sussex.
"This is the last thing that anyone wants or expects to happen."
A police spokesperson said the women's next of kin had been informed and formal identification was now being undertaken.
"It would not be appropriate to publicly name the women before these procedures are completed," they added.
It is not yet known how the women came to be in the water, but the coastguard ended its search and said it was not looking for anyone else.
Ch Supt Adam Hays, from Sussex Police, said it was a "sensitive investigation that includes a number of hypotheses".
"It would not be appropriate to speculate as we to continue to gather evidence," he added.
He is calling for the public's patience while the force establishes the "full facts".
It is understood that the women were first spotted at Brighton Palace Pier before drifting to the marina.
One line of inquiry police are exploring is that the women may have gone into the sea from the beach and then got into difficulty.
Officers said there was no evidence to suggest third-party involvement or criminality.
Anyone with information that could help police is asked to contact the force.
A large cordon was in place around the beach at Black Rock on Wednesday morning while emergency teams dealt with the incident. The beach was later reopened.
"This is an utterly heartbreaking tragedy," said Hays.
"My thoughts are with the loved ones of these three young women after their devastating loss.
"They will remain at the forefront of our minds as we search for the answers their families, and the wider public, desperately seek," he continued.
Guy Jones, from nearby Kemptown, said: "It's very sad for all of us who associate this part of the coastline with happiness and peace.
"To have lost three young women in the prime of their lives brings a great sadness to the whole community, as well obviously to the family and friends."
Brighton Marina resident Ash Middleton said: "It's very sad and I think it's just sad for Brighton as well.
"I'm a swimmer myself and the seas here are quite treacherous."
Judy, also from the Marina, said: "It just makes it feel more poignant and frightening actually that it can happen so close."
Peter Kyle, MP for Hove and Portslade, said the incident was a "sobering and heartbreaking reminder that our families, neighbours and communities are what is important".
"Our seafront is one of the many jewels in the crown of our city, but the sea can be a risk," he said on Wednesday.
"However, for tonight I shall only be thinking about the families and friends affected by this tragedy."
Labour's Sankey said the council had "worked hard to ensure we have the best possible coverage in terms of a lifeguard service, which obviously is increased over the summer months, but it is of course very challenging".
She added that the council had recently completed a seafront safety review.
The Brighton leg of an annual nationwide protest to hold the water sector to account has also been cancelled because of the incident.
Paddle Out, led by the Surfers Against Sewage campaign group, will see groups gather at more than 50 locations on Saturday.
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