Hungarian Prime Minister Viktor Orban has asked for a thorough investigation into a boat accident on the Danube River in central Budapest that killed at least seven South Korean tourists this week.
"One is shaken by this ... an accident happened where passengers had almost no chance for survival," Mr Orban told state radio, offering condolences to relatives of the victims.
"I have asked the authorities to carry out a strict and thorough investigation," he said.
Hungarian police said late on Thursday they had taken into custody the captain of a cruise ship involved in the accident.
Strong currents in the Danube River have prevented rescuers from reaching a sunken tourist boat. Source: AAP
The captain denies breaking any rules or committing a criminal offence, his lawyer said in a statement cited by state news agency MTI on Friday.
Hungarian police said late on Thursday they had taken into custody the captain of the 440-foot (135-metre) cruise ship, which hit and sank the smaller pleasure boat. It was so far unclear what caused the accident.
In the statement, the lawyer said treating the 64-year-old Ukrainian captain as a suspect was "premature, at the moment not more than a theory" as experts' opinions were not yet available.
The boat was cruising when it collided with a larger luxury passenger boat during a rainstorm on Wednesday evening, causing it to capsize and sink with 33 South Korean tourists, tour guides and two Hungarian crew aboard.
Seven South Koreans died, seven were rescued and 19 South Koreans were among the 21 people still missing. Hungarian rescue officials said on Thursday there was little chance of finding survivors.
Recovery operations continue after a deadly boat crash on the Danube River in Budapest, Hungary. Source: AAP
South Korean rescue teams and officials including South Korean Foreign Minister Kang Kyung-wha arrived in Budapest on Friday.
A crane ship was docked near the wreck in preparation for recovery operations. Police have said the rescue efforts were hampered by high water levels, strong currents and bad visibility.
