The captain of Viking Sigyn has been charged after seven people died when the river ship collided with a small sightseeing boat on the Danube in Budapest.

A Budapest court official reportedly said the captain of the Viking Sigyn had been charged, but gave no further details.

The 64-year-old Ukrainian national was detained on Thursday for questioning a day after his vessel collided with the smaller Mermaid, carrying mainly South Korean tourists, causing it to overturn and sink on a busy stretch of the Danube.

He was questioned for “endangering waterborne traffic resulting in multiple deaths”, police said at the time.

The captain’s lawyer, Balazs Toth, said the court had granted bail, but prosecutors were appealing it so his client remained detained.

“My client has not changed his statement made as a witness. He insists that he has not made any error,” his other lawyer, Gabor Elo, told reporters after the hearing.

Strong currents have hampered the search for those missing – 19 South Koreans, the second boat’s Hungarian captain and one crew member, preventing divers from reaching the submerged boat.

A Hungarian police spokesman said that seven of the South Korean victims have been identified but their names have not been released.

Seven people died with another 21 feared dead after the 27-metre sightseeing boat collided with the Viking ship during a rainstorm last Wednesday. The Mermaid sank seven seconds later, police said.

An ambulance spokesman said seven people rescued alive were suffering from hypothermia but stable.

Police Colonel Adrian Pal said: “Both ships were heading north and when they arrived between two pillars of the Margit Bridge, but for some reason the Mermaid turned in front of the Viking ship.

“As the Viking [ship] comes into contact with it, it overturns it and in about seven seconds, as it turned on its side, it sank.”