DEL MAR, Calif. (KSWB) — A smuggling boat dropped migrants in the water off the coast of Del Mar Friday morning, prompting a massive rescue effort for people struggling to swim to shore.

The San Diego County Sheriff’s Department got an emergency call around 4:30 a.m. about the swimmers, who were spotted off the coast near Torrey Pines. Dispatchers learned the boat had dumped an estimated 16 people in the water.

By 7 a.m., 11 people had been brought to shore or were able to swim to safety on their own, but the rescue effort was not slowing down, with officials searching by boat and helicopter for the remaining passengers. Two people were later found hiding in bushes on the beach nearby, bringing the total passengers found to 13, officials confirmed in a news conference.

That left three people unaccounted for as of 9 a.m., though authorities said it wasn’t clear whether the remaining migrants made it to shore and ran off, or if they were still in the ocean.

The boat the people had been riding in was a panga — a kind of small fishing boat with an outboard motor that is frequently used to bring people into the U.S. illegally — that likely came into the country from Mexico, Del Mar Fire Chief Mike Stein said. Stein referred to the smuggling tactic as a “dump and run.”

Crews rescue migrants from boat taking on water off California coast

The fire chief said most of the migrants were suffering from “mild hypothermia.”

U.S. Border Patrol was in the area to interview the passengers once they had received medical care. They were also searching for the boat as it likely headed back to Mexico, Stein said.

The U.S. Coast Guard, Del Mar Fire Department and San Diego Fire-Rescue were also involved in the rescue. Divers were brought in later Friday morning to continue the search for the three remaining people.