Sharks are washing up on a beach in Massachusetts frozen completely solid amid a record-breaking cold snap in the United States.

The Atlantic White Shark Conservancy said it had found three dead thresher sharks stranded on the shore of the Cape Cod Bay in Brewster, south of Boston, in the last three days.

The first two were "likely stranded due to cold shock" it said. The third was frozen solid.

The sharks were likely stranded while trying to reach warmer waters. ( Supplied: Atlantic White Shark Conservancy )

"This shark was too frozen to attempt a necropsy … a true sharkcicle," it said.

Thresher sharks are found all over the world and generally stay far away from the shore, in warmer waters.

"These sharks were most likely moving to the south with the warmer water and got caught in the hook of Cape Cod," the group said.

The minimum temperature for the Cape Cod region in December is usually about 1 degrees Celsius, but current forecasts have it reaching as low as -12C.

The Atlantic White Shark Conservancy said all three sharks would be examined once they thawed.

Meanwhile, sea turtles are also feeling the cold.

The National Oceanic and Atmospheric Administration (NOAA) said it rescued more than a dozen sea turtles off the coast of Galveston Island that were "cold-stunned by freezing air temperatures".

The lethargic sea turtles were found by fisherman and taken to NOAA's Sea Turtle Hospital to recover.

"All 18 turtles were brought in for rehabilitation, where their body temperature was slowly increased prior to placement into water," the group said.