Jakarta: At least 128 passengers were missing after a ferry sank in Indonesia's Lake Toba on Monday evening, a search and rescue official said on Tuesday.
"Many people have reported their relatives missing," Budiawan, head of the search and rescue agency based in the nearby city of Medan, told Reuters after a coordination meeting.
Authorities had previously said at least 80 people were thought to be on board the ferry that sank in rough weather.
Earlier in the day, Indonesian rescue workers fought heavy rains and two-metre waves in a search for survivors.
An estimated 18 people had been rescued and one passenger was confirmed dead after the ferry sank on Monday. Some 100 rescue personnel, including military and police officials, were deployed in the search.
It was not immediately clear if foreigners were among the missing passengers.
"Our joint teams moved out at 7am," said Budiawan, head of the search and rescue agency in the nearby city of Medan, adding that the teams would work for as long as the weather allowed.
"It might take time to find victims who drowned," he said, adding that some bodies may be trapped inside the sunken vessel.
Video footage provided by the agency showed people on another ferry throwing life preservers and life jackets to several people in the water on Monday evening.
On Tuesday, distressed relatives of missing passengers held each other and cried as they waited for news at Tigaras Port, according to pictures from the scene.
Ferry accidents are common in Indonesia, a vast archipelago, especially during the holiday of Eid when millions of people make the annual journey by land, sea and air to their hometowns after the holy fasting month of Ramadan.
A longboat carrying around 43 people sank off Makassar on Sulawesi island last week, killing 13, and a speedboat carrying 30 passengers sank off South Sumatra, killing at least two.
Lake Toba, a popular tourist destination, fills the caldera of a giant dormant volcano and is one of the deepest lakes in the world.