Updated

The search is on for the more than 190 people feared dead after a crowded tourist boat sank on an Indonesian lake earlier this week.

Indonesian authorities say the boat was five times over its passenger capacity and only 18 survivors were found within the hours of the sinking on Monday evening.

It's possible many of the victims were still inside the sunken ferry, said North Sumatra province police chief Paulus Waterpau.

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Relatives of victims of a sunken ferry weep as they wait for news on the search efforts. (Associated Press)

The tourist boat, which was only equipped with 45 lifejackets, sank about 20 minutes into its trip when strong high waves caused the boat to take on water and then capsize.

"Many passengers without a life jacket jumped into the deep lake, but others drowned with the boat," survivor Juwita Sumbayak told the Associated Press. "I jumped, I cried with fear." She saw dozens of people in the water "but nobody can help."

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Several dozen divers and up to 350 others searched Lake Toba, which has depths of more than 1,000 feet, but only found personal belongings and traces of oil. (Associated Press)

Several dozen divers and up to 350 others searched Lake Toba, which has depths of more than 1,000 feet, but only found personal belongings and traces of oil.

According to the AP a cell phone video showed the crew of a passing ferry attempting to rescue people in the waters shortly after the sinking but efforts were hampered by bad weather.

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Relatives of the victims wait for news on any survivors. (Associated Press)

Suwarni, whose 20-year-old son and his girlfriend were on the ferry, criticized the search and rescue operation as slow and insufficient.

"Millions of questions keep me from sleeping," said Suwarni, who uses one name, between desperate sobs.

The lake is a popular tourism destination in northern Sumatra but it is still unclear whether any foreigners were victims in the tragic sinking the Jakarta Post reported.

The Associated Press contributed to this report.