Relatives of the South Korean passengers on board a sightseeing boat on the Danube that collided with a river cruise vessel were today flying in to Budapest as investigators continued to probe how the accident happened.

Rescue workers are still searching the river in freezing conditions and divers hope to reach the sunken sightseeing ship today. It is likely the death toll will rise, though one man was found alive 3 kms downstream last night.

The boat was carrying 33 South Korean passengers and two Hungarian crew when it collided with the Viking Sigyn travelling in the same direction during a night-time tour on Wednesday night.

Seven people were confirmed as dead and 21 others are missing. Seven people were rescued.

Hungarian Police said Thursday that the small sightseeing boat, the Hableany (”Mermaid”), crashed with the Viking  at 9:05 p.m. local time Wednesday night beneath

The 64-year-old Ukrainian captain of the Sigyn is in custody.  He is being questioned over endangering water transport leading to a deadly mass accident, police said in a statement on their website on Thursday.

In line with Hungarian laws, the suspect was identified only as Yuriy C, referring to his first name and the initial letter of his last name.

So far just seven of the 35 people on board, which included 33 South Koreans, are known to have survived Wednesday’s incident near the Hungarian Parliament in Budapest.

Seven others are confirmed dead and 21 remain missing.

Police were reported as saying they detained the Odessa resident after questioning him and have proposed his arrest.

“Both ships were heading north … and when they arrived between two pillars of the Margit Bridge, for some reason the Hableany turned in front of the Viking ship.

Screen Shot 2019 05 30 at 9.12.43 pm“As the Viking comes into contact with it, it overturns and in about seven seconds, as it turned on its side, it sank,” Col Zsolt Gabor Palotai, head of Budapest’s disaster management office, told reporters.

Video footage showed that the two vessels were traveling closely side by side as they approached the bridge in central Budapest. It was not immediately clear what caused the collision.

Police Col. Adrian Pal told reporters “Several people fell into the water from the ‘Hableany’.”

Seven people are confirmed dead, and 21 are still missing. Seven others were rescued at the scene.

Police said none of the bodies were found wearing life jackets.

Screen Shot 2019 05 30 at 9.14.15 pmCCTV footage recorded on Wednesday night showed that the river was busy with boats of different sizes traveling in both directions.

According to Associated Press, Viking Cruises said one of its ships was involved in a boat collision.

Viking said in a statement: “The Viking river ship Sigyn was involved in a collision with another vessel – a Hungarian tourist ship – on the Danube River in Budapest yesterday evening (29th May).

“Sadly, there have been reports of fatalities and we offer our heartfelt condolences to those affected by this tragic accident. There were no injuries to Viking crew or Viking guests. We have been and continue to cooperate fully with the authorities while they undertake their investigations.”

Officials in Seoul say seven South Korean tourists are dead and 19 others are missing after their sightseeing boat collided with a larger cruise ship and capsized. Two Hungarian crew are also missing.

According to reports, video footage shows the 442ft Viking Sigyn colliding with the 89ft Mermaid close to the Parliament building amid torrential rain.

According to the Daily Mail, the Viking appeared to collide with the Mermaid from behind, before the smaller Soviet-era vessel, which was carrying  35 people, spun sideways on impact.

The Mermaid then capsized before sinking in just seven seconds on a fast-moving stretch of the river which has swollen during heavy downpours throughout May.

Hungarian Prime Minister Viktor Orban and President Janos Ader sent condolences to Seoul. ‘We are with the victims and their families in our thoughts and prayers in these most difficult times,’ Orban said, according to his spokesman.

Police were searching the river throughout the entire length of the Danube in Hungary south of where the incident took place.

The temperature of the river water is between 10 and 15 degrees.

The accident happened on a popular part of the Danube river for pleasure trips, from where passengers can view the city and parliament building illuminated at night.

Heavy rainfall since the beginning of May has led to high water levels and a fast-moving river current, complicating rescue efforts.

Most of the Koreans were family groups, and they included a six-year-old girl. Her status wasn’t immediately clear.