Survivors of the Budapest tour boat disaster say they barely had time to grab hold of a drifting lifeboat while watching in horror as others around them struggled in the dark, rainy waters.
Only seven of the 35 people on the boat, including 33 South Koreans, were rescued. Seven others have been confirmed dead and 21 are missing.
Survivors said the small sightseeing boat had almost finished an hour-long night tour of the Hungarian capital on Wednesday and was nearly at its stop when a larger cruise ship hit it under a bridge near the parliament building, a city landmark.
They said about 20 people were on the deck taking photographs or preparing to disembark. The others were in the cabin.
"I saw that big cruise ship coming closer to us but I never imagined it would ram our boat," a 31-year-old South Korean named Jeong told the Yonhap news agency.
She and others on the deck were thrown into the cold Danube waters by the impact of the collision. Police said it took only seven seconds for the boat to overturn and sink.
"Our boat was turned over in an instant and began sinking," Yoon, 32, told Yonhap. "All those on the deck fell into water and I think those staying in the cabin on the first floor probably couldn't get out of the ship swiftly."
While holding onto the lifeboat together, Jeong and Yoon said they shed tears when they saw the heads of other people coming up and down in the fast-moving river.
"The people had been plunged into the river in the darkness and shouted 'Help me!' while floundering in the waters. But I couldn't do anything for them," Jeong said, crying.
Police launched a criminal investigation and detained and questioned the Ukrainian captain of the larger cruise ship. The 64-year-old man is suspected of endangering water transport leading to a deadly mass accident.
The South Koreans, mostly family groups, were on a package tour of Europe. Yoon was travelling with her mother, aunt and uncle. After she was rescued, she called her father in Seoul to tell him that she and her mother had survived. The fate of her two other relatives is unknown.
It was still unclear what exactly caused the collision. A preliminary investigation showed that none of the South Koreans was wearing a life jacket at the time of the accident. Some experts in South Korea also raised questions over why the boat tour was allowed to proceed in the heavy rain with strong currents and compromised visibility.
"There's always a possibility of accidents when you decide to sail in those conditions," said Yun Jong-hwui, a professor at the Korea Maritime and Ocean University.