A popular southern California beach was closed after a great white shark was reportedly spotted “exhibiting aggressive behavior” on Tuesday afternoon.

The Huntington Beach fire department said there was a “credible report” of a 10-12ft great white shark circling near a lifeguard tower, which is considered aggressive behavior according to the city’s marine safety division’s “shark response protocols”.

Officials closed a two-mile long stretch of beach near the tower between Seapoint and the Huntington Beach pier through Wednesday afternoon, and said workers had posted warning signs and notified visitors.

“Please follow all posted signs and instructions from lifeguards. Public safety remains our top priority,” the city’s fire department said in a statement.

The Orange county beach is popular with surfers and swimmers.

California saw an unusually high number of great white sharks over the summer as juveniles fled warm waters in Mexico amid El Niño. Experts said humans shouldn’t be alarmed.

Shark incidents involving bites are “extremely rare” in California, according to the state’s department of fish and wildlife. There have been fewer than 250 shark incidents in the state since 1950, and fewer than 20 were fatal.

Scientists agree that such incidents are generally “exploratory bites” as a result of sharks investigating “unusual objects in their environment, such as kayaks”, the fish and wildlife department said.