More than a dozen great white sharks have been spotted along the Southern California coast, sparking urgent warnings to paddle-boarders to get out of the water.
Video posted online by the Orange County Sheriff's Department shows the sharks swimming near several people in the water at Dana Point.
The group were warned by officers who flew over the area in a helicopter.
"You are paddle-boarding next to approximately 15 great white sharks," deputy Brian Stockbridge announced over the helicopter loudspeaker.
"They are advising you exit the water in a calm manner. The sharks are as close as the surf-line."
Advisories have been posted for beaches up and down Southern California after shark sightings this week - including at San Onofre State Beach where a woman was bitten by a shark on April 29.
She is recovering from wounds to part of her upper thigh.
Sightings are not uncommon along the coast, but attacks are rare.
Fire captain Cameron Abel, of the Marine Safety Unit in Long Beach, said the increase in shark sightings is similar to an influx seen at this time last year.
Marine safety officials have attributed the activity to a "thriving aquatic ecosystem" in the area and estimated that 10 to 20 juvenile sharks swim near Long Beach daily.
The sharks "were around most of the summer", Mr Abel told the Los Angeles Times. "We'd spot them periodically, and towards the end of the summer they disappeared."
Nearly a year ago, a woman was bitten by a shark while swimming off Corona del Mar, about 15 miles to the north of the latest sighting of the group of sharks.
Experts estimated the shark was at least 10 feet in length, judging from the bite marks.