At least 11 people believed to still be missing, with rescue operations underway.

The US coastguard has said it rescued 16 people from the Pacific Ocean after a boat sank off Mexico’s Baja coast.

The coastguard said on Friday it responded to a Mayday call reporting that a boat was sinking. The search is ongoing for 11 people believed to be still missing.

The boat went down about 225km (140 miles) west of Ensenada, Mexico.

A rescue helicopter reached the site about two hours after someone on the boat transmitted the Mayday call at about 1am (08:00 GMT) on Friday, said coastguard Lieutenant Santiago Tamburini.

It took about 90 minutes for the coastguard crew, which included a rescue swimmer, to pull the 16 people from the water, Tamburini said.

The people rescued were Mexican nationals, according to the Mexican consulate.

One survivor was being treated for a suspected shark bite and two were in critical condition, authorities said.

The rescued were flown by helicopter to San Diego, California, and transported to hospitals. The Mexican consulate in San Diego said it offered consular assistance.

The coastguard and US Navy are continuing to search the area with two helicopters, a fixed-wing plane, a cutter and a navy combat ship.

The boat sank in an area frequented by smugglers transporting migrants to the US. It is also popular with fishing and leisure boats.

Details about the boat’s origin, destination and what it was doing are not clear. No vessel, only debris, was found, and it was unclear what type of boat was involved, the coastguard said.

“Boats in that area can be for fishing, leisure, personal recreation. We just don’t know what they were doing out there. We all know it’s a suspected smuggling route,” Tamburini said.