According to Reuters, authorities in the Hungarian capital ordered the 64-year-old Ukrainian national be held on Saturday (1 June) as investigations into the collision involving Viking River Cruises’ Viking Sigyn continued.

It is understood the ship hit the tourist boat, which was carrying a party of South Korean visitors, during heavy rain, sinking it almost immediately.

Seven of the tourists onboard the smaller ship have been confirmed dead, with another 21 still understood to be missing, the BBC reports. Seven were rescued alive.

In total, there were 35 people onboard the boat – 30 South Korean tourists, who were travelling with the country’s Very Good Tour company, three tour guides and two Hungarian crew.

The incident happened at about 9pm local time (7pm GMT) near Budapest’s Margit Bridge, a few hundred metres north of the Hungarian parliament building on the river front.