The captain of a river cruise ship that collided with a smaller sightseeing vessel was charged Saturday over the accident in Budapest that killed seven South Korean tourists and left 21 missings.

The Mermaid carrying mainly South Korean tourists overturned and sank late Wednesday, seconds after colliding with the Viking Sigyn cruise ship on a busy stretch of the Danube in the heart of Budapest.

Strong currents have hampered the search for those missing — 19 South Koreans and two Hungarians — preventing divers from reaching the submerged boat.

The Siggyn’s Ukrainian captain was charged Saturday, a Budapest court official told AFP but gave no further details.

The 64-year-old was detained Thursday for questioning for “endangering waterborne traffic resulting in multiple deaths”, police have said.

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

“He is devastated by the number of victims and is asking constantly that condolences are conveyed to their families,” Toth said.

“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.

Near the accident site, a floating crane has been erected, as well as a small pier for use by divers.

But with the Danube swollen after weeks of rain, the strong current has complicated plans to lift the wreck, and the prospects of finding any of the passengers alive are seen as very slim.

Serbia, Romania and Croatia — countries along the Danube, south of Hungary — have been asked to help in the search after South Korean Foreign Minister Kang Kyung-wha insisted in Budapest on Friday her country would not give up hope of finding survivors.

One of the bodies had been found about 11 kilometres (seven miles) downstream of the accident site.

South Korean relatives of the Mermaid passengers arrived in Budapest Friday, and officials took them to the banks of the Danube.

The Hungarian Magyar Nemzet daily, meanwhile, on Saturday quoted police reports as saying the Sigyn might not have warned the pilot of the smaller ship that he was going to overtake.

According to the newspaper, he also did not alert police about the collision.

People have been laying flowers along the river bank and on a bridge near the collision site, as well as at the South Korean embassy.

On Saturday, black flags were flying along the bridge.

Only seven people are known to have survived so far. Those missing include a six-year-old girl, as well as the Mermaid’s Hungarian captain and a crew member.

The collision happened on a popular part of the river from where sightseers can view the city and parliament, which is lit up at night.

Larger river cruise boats travelling on the Danube between Germany and the Black Sea typically spend several days moored in the capital.