A Ukrainian man captaining a cruise ship that collided with a Hungarian sightseeing boat Wednesday night, killing at least seven people, has been arrested on suspicion of endangering water transport, police said.

The man, identified only as Yuriy C., was taken into custody on Friday after investigators said “material evidence” collected from the scene pointed to “reasonable suspicion” that the 64-year-old captain of the Sigyn “committed the crime of endangering water traffic causing a fatal mass disaster,” Hungarian Police said in a statement.

Further interrogation of the suspect led police to suggest that they initiate his “pre-trial detention.”

SOUTH KOREAN TOURISTS WERE NOT WEARING LIFE JACKETS IN FATAL BOAT COLLISION THAT LEFT 7 DEAD, 21 MISSING: OFFICIALS

At least seven people are dead, and 21 more are missing after a sightseeing ship carrying 33 sightseeing tourists and two Hungarians collided with the Viking cruise ship in the Danube River Wednesday.

Police said Thursday that the small passenger boat, the "Hableany,” crashed with the Viking boat at 9:05 p.m. local time Wednesday night beneath the Margit Bridge.

"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,” Police Col. Adrian Pal said. As the Viking comes into contact with it, it overturns it and in about seven seconds, as it turned on its side, it sank.”

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

SURVIVORS OF BUDAPEST BOAT SINKING RECALL CHAOTIC MOMENTS

All the deaths were confirmed to be South Korean citizens. An additional seven people were rescued and they too were said to be South Korean.

Viking released a statement on Thursday confirming that one of its vessels was involved in the fatal collision but that no one aboard was injured. The company said that it is cooperating with authorities.

South Korea’s Foreign Ministry office said Friday that none of the passengers involved in the accident were wearing life jackets at the time of the collision, adding that it was “customary” for tourists on this particular tour not to wear them.

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South Korea sent a team of 25 people, made up of members from the country's national fire agency, navy and coast guard, to help support Hungarian rescue efforts.

The victims were a group of tourists that left South Korea on May 25 as part of a group touring Europe, a South Korean travel agency, Very Good Tour, said. They were set to return on June 1.

The Associated Press contributed to this report.