Indonesian rescuers are battling strong currents on Friday as they resume the search for 30 people still missing at sea about 35 hours after a ferry sank killing at least six people, officials said.

Indonesian rescuers were searching for 29 people who remained missing Thursday after a ferry sank and six people died the previous night near Indonesia’s resort island of Bali.

Indonesian authorities intensified a search operation for 30 people missing after a ferry sank near the tourist island of Bali.