The victim was swimming at Rockaway Beach in New York City at around 6pm on Monday when the deadly sea creature attacked her left leg.

The shark bite removed a chunk of the woman's flesh, leaving a gaping wound several inches wide and deep.

It was the most serious shark attack in New York waters since at least the 1950s, said Gavin Naylor, the programme director of the International Shark Attack File at the University of Florida.

The woman, who has not been named, remained in critical condition at Jamaica Hospital Medical Center, spokesperson Michael Hinck said, according to NBC News, Sky News' US partner network.

New York has seen an increase in such attacks in recent years, but most bites involve smaller sharks mistaking a person's ankle or lower leg for a fish, resulting in minor grazes or puncture wounds.

In the past two summers, at least 13 swimmers have reported being bitten in the state - more than the total number of bites in New York history before 2022.

'Unlike anything we've seen'

But Mr Naylor said: "This is something qualitatively different."

He said the bite mark was most consistent with a juvenile white shark, though he said it may have also been a bull shark or sandbar shark.

"This is a very severe injury from something that's powerful and unambiguous," he said.

"It's very deliberate."

Christopher Paparo, the manager of Stony Brook University's Marine Sciences Centre, agreed the wound was "unlike anything we've been seeing".

Authorities banned swimming at the beach on Tuesday as police searched for sharks but none were spotted.

But a beach around 25 miles away on Long Island was closed on Tuesday after officials spotted multiple sharks near the shoreline.

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Sand tiger sharks spotted in large numbers off Long Island

Several shark attacks were reported northeast of Rockaway last month, in the waters off Fire Island, Quogue and Babylon, with officials saying they were most likely sand tiger sharks.

Sand tiger sharks, which can grow up to 10ft, have been spotted in relatively large numbers along the surf line off Long Island this summer, according to NBC News.

Experts at the Florida Museum's International Shark Fish Attack File say they are attracted to the bays and baitfish off the Long Island coast.

A spokesperson for the Parks Department, Meghan Lalor, said: "Though this was a frightening event, we want to remind New Yorkers that shark bites in Rockaway are extremely rare.

"We remain vigilant in monitoring the beach and always clear the water when a shark is spotted."