BANJARMASIN, Indonesia — Indonesian rescue teams expanded their search Monday for 129 people missing after a passenger ferry overturned in severe weather in the Java Sea, killing at least six people. The Virgo Transport 8 was traveling from Surabaya in East Java to Banjarmasin in South Kalimantan when its captain sent a distress call reporting that the vessel was listing in rough seas. Waves reached as high as 3 meters, or about 10 feet, according to officials. Authorities lost contact with the ferry around 2 a.m. Sunday. About two hours later, they learned the vessel had overturned in the Masalembo waters, roughly 148 kilometers, or 92 miles, from Banjarmasin. Rescuers saved 108 people and recovered six bodies Sunday, assisted by tugboats and other vessels in the area. On Monday, the National Search and Rescue Agency deployed 17 ships and aircraft, along with about 622 personnel from the military, police and other agencies. Specialized underwater teams and navy-operated underwater drones were being added to the operation to help locate survivors and recover victims. “We remain hopeful of finding more survivors,” rescue agency chief Mohammad Syafii said during a video briefing. The ferry’s manifest listed 243 people aboard: 213 passengers and 30 crew members. Officials said passenger totals can differ from manifests, a discrepancy that could complicate efforts to identify everyone who was on board. The ship was also carrying 89 vehicles. Relatives gathered at a rescue command center at Banjarmasin’s Trisakti port and at a port in Surabaya, Indonesia’s second-largest city, waiting for information about family members believed to be missing. The 119-meter, or 390-foot, ferry was built in Japan in 1987 and sold to Indonesia last year. Ferries are a critical part of daily life across Indonesia, an archipelago of more than 17,000 islands. The country has experienced repeated maritime disasters, with safety advocates pointing to gaps in enforcement of vessel and passenger-safety rules. The scale of the latest search underscores the risks faced by communities that depend on sea travel when storms and rough conditions intensify.