At least 15 people have died after a ferry carrying more than 350 passengers and crew members onboard sank in the waters off the Philippines' southern coast. Search crews have rescued 316 people on board the MV Trisha Kerstin 3, but at least 28 people are still missing. The ship, which was both a cargo and passenger ferry, was on its way from the country's southern mainland, Mindanao, to Jolo island further south-west when it issued a distress call at 1:50 local time Monday (17:50 GMT Sunday). Authorities say they are investigating the cause of the sinking. The Philippines - an archipelago nation of 7,100 islands - has a long history of maritime disasters involving inter-island ferries. According to Philippine Coast Guard spokeswoman Noemie Cayabyab, survivors reported that the waters in the area were rough at the time. A Facebook video by Basilan Governor Mujiv Hataman showed survivors wrapped in blankets as they disembarked from rescue boats. Rescuers have been overwhelmed by the influx of survivors, with emergency responder Ronalyn Perez highlighting staffing shortages facing their team. Past ferry accidents in the Philippines have often been attributed to poor maintenance and overloading. Despite these risks, many Filipinos rely on ferries for affordable transportation. Recent incidents have also raised alarm, including a fire in May 2023 that resulted in 28 fatalities, including young children. As the nation awaits further updates on this tragedy, safety measures in the ferry industry come under renewed scrutiny.