At least 15 people have died after a ferry with more than 350 people sunk early on Monday near an island in the southern Philippines, according to local officials, with the coast guard warning that 28 people remained missing.

The M/V Trisha Kerstin 3, an inter-island cargo and passenger ferry, was sailing to southern Jolo island in Sulu province from the port city of Zamboanga with 332 passengers and 27 crew members when it apparently encountered technical problems and sank after midnight, coast guard officials said.

The ferry sank in good weather about a nautical mile (1.8km) from the island village of Baluk-baluk in Basilan province, where many of the survivors were initially taken, coast guard commander Romel Dua told The Associated Press.

“There was a coast guard safety officer on board and he was the first to call and alert us to deploy rescue vessels,” Dua said, adding that the safety officer survived.

Coast guard and navy ships, along with a surveillance plane, an air force Black Hawk helicopter and fleets of fishing boats were carrying out search and rescue operations off Basilan, Dua said.

Mujiv Hataman, Basilan provincial governor, said several passengers and two bodies were brought to Isabela, the provincial capital, where he and ambulance vans waited.

“I’m receiving 37 people here in the pier. Unfortunately two are dead,” Hataman told the Associated Press.

The coast guard said 316 passengers had been rescued and at least 15 bodies found.

The cause of the ferry sinking was not immediately clear and there will be an investigation, Dua said, adding that the coast guard cleared the ferry before it left the Zamboanga port and there was no sign of overloading.

Sea accidents are common in the Philippine archipelago because of frequent storms, badly maintained vessels, overcrowding and spotty enforcement of safety regulations, especially in remote provinces.

In December 1987, the ferry Dona Paz sank after colliding with a fuel tanker in the central Philippines, killing more than 4,300 people in the world’s worst peacetime maritime disaster.