May 30 (UPI) -- Nearly two dozen people are still missing in Hungary after a tourist boat sank in the Danube River and killed seven, authorities said Thursday.
The tourist vessel, carrying South Korean sightseers, collided with another boat Wednesday in Budapest. Hungarian authorities have started a criminal investigation, and say none of the tourists aboard wore life jackets.
Seven people were rescued from the Danube, but officials said there's only "minimal hope" for more survivors. Twenty-one are still missing.
The crash happened near the capital's city center and Hungarian Parliament building. Officials said heavy rains Wednesday caused the river to swell, and the tourist boat crashed into a larger passenger boat near one of the bridges. Police said it could take days to lift the sunken boat from the riverbed.
Panorama Deck, which operated the tourist boat, has not yet determined a cause for the crash. The boat, named Hableany, or "The Mermaid," has operated on the Danube River since 2003.
"It was just an average day and this was a regular trip," Panorama Deck spokesman Mihaly Toth said. "We carry out thousands of tourist boat trips every day, there were no signs that something like this could happen."
Very Good Tour CEO Lee Sang-moo told reporters in Seoul that the group was on the fourth of a nine-day tour through Croatia, Slovakia, Czech Republic, Hungary, Austria and Germany.
"I deeply apologize to the parties affected by the accident, families of victims and the people who are suffering after hearing the news this morning," Lee said. "I understand that the boat took every precaution."