A ferry carrying at least 600 passengers broke apart and sank in Indonesia's Java Sea when a violent storm sent towering waves over its deck, officials said Saturday.
"We're afraid many have died," said Slamet Bustam, an official at Semarang port, where hundreds of distraught relatives and friends waited for news about their loved ones.
The Senopati went down around midnight Friday en route to the Java port from the northern island of Borneo - a 49-hour journey. Around 14 hours after the disaster, 66 survivors had been found, many of them drifting in lifeboats, officials said.
Authorities were struggling to come up with an accurate number of people onboard, as waves of up 5 meters (16 feet) made it hard to reach the accident site.
In a last radio contact, the captain informed port authorities that the ship was severely damaged and capsizing, said local navy commander Col. Yan Simamora.
"We all just prayed as waves got higher," said Cholid, a passenger who survived by clinging to some wooden planks, but lost his 18-year-old daughter. "The ship broke up after turning upside-down," he said.
Panicked passengers fought over life jackets as the boat capsized, sending cars crashing into one another in the cargo hold, he said.
"I was going upstairs to try to help my daughter, but the ship suddenly broke up and I was thrown out. I lost her," said Cholid, who like many Indonesians uses one name.
Worried family members gathered at the main office of ferry operator PT Prima Fista in search of news.
"I am waiting for my mother, auntie, sister and nephew who were on their way to celebrate New Year's Eve at my house," said Yulis, 25.
Transport Minister Hatta Radjasa put the number onboard at 542, citing the passenger manifest, but ships in Indonesia often carry far more people than recorded.
The ferry ran into trouble around 40 kilometers (24 miles) off Mandalika island, some 300 kilometers (190 miles) northeast of the capital, Jakarta, while en route to Semarang on Central Java from Kumai on Borneo island.
Seasonal storms have wreaked havoc across Indonesia in recent days, triggering flash floods and landslides that have killed more than 145 people and driven hundreds of thousands from their homes on Sumatra.
Earlier Friday, a different vessel carrying around 100 people capsized in bad weather off the coast of northwestern Sumatra, killing three and leaving 26 missing, Radjasa told the AP.
Ferries are a main source of transportation in Indonesia, a vast archipelago of more than 17,000 islands with a population of 220 million.