At least seven people are dead and 21 others are missing after a sightseeing boat capsized on the Danube River in Budapest on Thursday. The boat was carrying 33 South Koreans—30 tourists along with two guides and a photographer—when it collided with another vessel before sinking, authorities said. Rescue efforts are underway for the 21 passengers who remain missing, and seven of those on board the South Korean Very Good Tour boat were rescued, according to South Korea’s Ministry of Foreign Affairs. Mihaly Toth, a spokesman for boating company Panorama Deck, which operated the capsized vessel for the tour company, said the cause of the crash is still under investigation. “It was just an average day, and this was a regular trip. We carry out thousands of tourist boat trips every day, there were no signs that something like this could happen,” Toth said in an interview on state television. South Korea’s President Moon Jae-in has ordered a rapid-response team to help out with the rescue effort in Hungary, a spokesperson in Seoul said.