At least seven people are dead after a collision with a Swiss cruiser on the River Danube in Budapest, Hungary, on Wednesday night.
The captain of the Swiss vessel has been detained and accused of "criminal negligence", according to Hungarian justice officials.
Search operations for more the than 20 people, mainly South Korean tourists as well as two Hungarian crew members, still missing have been hampered by high water on Saturday.
There were 35 people on board the "Hableany" (Mermaid) when it collided with the "Viking Sigyn", which belongs to Basel-based Viking River Cruises. The Hableany sank while Swiss vessel escaped relatively unscathed.
Seven Koreans on the Hableany were rescued and were found in a state of hypothermia. They have been admitted in a hospital and are in a stable condition.
According to the South Korean news agency Yongap, 30 tourists and three guides were travelling through six Eastern European countries on the Hableany. Most of them are in their forties, but a six-year-old child was also on board.
A Viking spokesman told Swiss news agency Keystone-SDA that nobody aboard the Viking hotel ship had been injured. He said that the company was cooperating with the investigation being led by the Hungarian police.
Swiss public television, SRFexternal link, released this clip on Thursday afternoon:
"Investigations by the Swiss representation in Budapest are underway," the Swiss Foreign Ministryexternal link told Keystone-SDA on Thursday afternoon, noting that there were no reports of Swiss victims.
The South Korean travel company "Verygoodtour" has expressed its condolences and pledged to help the victims and their families. Meanwhile, the South Korean authorities have said they would send a rescue team.