MANILA — A ferry with more than 340 people onboard sank early on Monday in choppy seas off the coast of the southern Philippines, killing at least 18 and leaving 10 still missing, the coast guard said.

The MV Trisha Kerstin 3 issued a distress signal around 1:50 am, a bit over four hours after it departed the port city of Zamboanga on the southwestern tip of Mindanao, the coast guard said in a statement.

A video released by the governor of Basilan Province showed barefoot survivors being wrapped in blankets and placed on gurneys, while victims of the sinking were carried past in body bags.

The triple-decker vessel went down on nearly the same route where 31 people died in 2023 after a fire aboard the Lady Mary Joy 3 ferry. Both ships were owned by locally based Aleson Shipping Lines.

Search-and-rescue efforts were expected to continue through the night, Philippine Coast Guard spokeswoman Noemie Cayabyab told Agence France-Presse, adding that an earlier tally of passengers had been reduced to 344 as some on the ship's manifest never boarded.

Sheryl Balondo, a rescuer in Isabela City, one of two municipalities where survivors were being taken, said their office had received more than 100 phone calls from concerned family members.

"There's a tug in our hearts whenever we pick up a call. Their voices sounded worried," she said."What we can only say is that, as of now, we don't have the final list (of names), because the search and retrieval operation is ongoing."

The 44-meter ferry went down about 5 kilometers east of Baluk-Baluk Island, part of the Basilan Province chain of islands off the Zamboanga Peninsula.

"Based on the account of some survivors, the waters in the area were rough at the time," Cayabyab said in a televised interview.

Basilan emergency responder Ronalyn Perez told AFP that rescuers were struggling to handle the influx of survivors.

"The challenge really is the number of patients that are coming in. We are short-staffed at the moment," Perez said.

A video released by the Philippine Coast Guard showed survivors being plucked from the water and receiving medical attention.