PACIFIC GROVE — Authorities continued searching Monday for a swimmer reported missing off Lovers Point in Pacific Grove after witnesses said she may have encountered a shark while swimming offshore.

According to the Pacific Grove Police Department, officers were called at 12:04 p.m. on Sunday to a report of a missing swimmer near Lovers Point. The swimmer, identified as a 55-year-old woman, had been participating in a regular open-water swim with a group that meets weekly in the area.

Police said the group entered the water as usual, but around noon a shoreline witness reported seeing a “large splash.” The sight prompted the other swimmers to return to shore out of concern it may have been a shark. All swimmers returned safely, except the missing woman.

“She’s a 55-year-old blonde woman with blue eyes who is currently missing and who we’re searching for,” said Pacific Grove Police Commander Brian Anderson.

Two witnesses told authorities the swimmer may have encountered a shark while swimming offshore. Law enforcement officials said shark sightings along the Central Coast are rare but do occur, and investigators believe the incident may be consistent with a shark encounter based on the witness accounts.

A joint command was established by the Pacific Grove Police Department and the Monterey Fire Department, with assistance from the U.S. Coast Guard, the Monterey County Sheriff’s Office, California State Parks, Seaside Fire and CAL FIRE. Search efforts included rescue boats, drones and helicopters.

According to the Coast Guard, a small boat crew from Monterey and multiple helicopter air crews from San Francisco were deployed. Petty Officer Christopher Sappey said one report described a disturbing sighting, but emphasized there is no confirmation of a shark attack.

“I can confirm that there was a reported sighting in the area, however we cannot necessarily correlate this sighting with the missing person as there is no confirming evidence of that,” Sappey said.

By 8 p.m. Sunday, the swimmer had not been located. Search operations were suspended overnight and resumed Monday morning with the same agencies involved. Authorities said the swimmer’s family has been notified.

As a precaution, Lovers Point Beach in Pacific Grove and McAbee and San Carlos beaches in Monterey will remain closed through Tuesday. A beach advisory will also remain in effect through Tuesday for Asilomar State Beach, Monterey Municipal Beach, Del Monte Beach and Monterey State Beach.