None of the seven South Koreans who died after a boat collision on the Danube River in Budapest on Wednesday night were wearing life jackets, authorities said.

Thirty-fivepeople — including 33 South Koreans — were on board the boat when it collided with another vessel in theHungarian capital Wednesday night, according to South Korean’s Ministry of Foreign Affairs (MOFA). The collision occurred in the city center.

Seven tourists and one Hungarian crew member died, a MOFA spokesperson told CNN Thursday. The other ship is being investigated.

Seven people were saved. However, South Korea’s President Moon Jae-in said in a statement that rescue efforts had been hampered by poor weather.

Very Good Tour’s chief operating officer, Lee Sang-moo, said at a press conference in Seoul on Thursday that the group was on the fourth day of a nine-day tour around Croatia, Slovakia, Czech Republic, Hungary, Austria and Germany.

Most of the tourists were middle aged, Lee added. The oldest was in their 70s — while the youngest was born in 2013.

“I deeply apologize to the parties affected by the accident, families of victims and the people who are suffering after hearing the news this morning,” Lee said.

“I understand that the boat took every precaution.” Mihaly Toth, a spokesman for boating company Panorama Deck, which operated the capsized ship, said the company could not confirm why the boat sank.

“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.

The tourist boat, called The Mermaid, had been operating on the Danube since 2003 and there had been “no signs of a possible issue with the boat,” he added.

Panorama Deck “ensures all the necessary technical maintenance is carried out every year,” he said.

South Korea’s President has ordered a rapid response team to be dispatched to help the rescue effort in Budapest, a presidential spokesperson in Seoul said Thursday.

South Korea’s Foreign Minister Kang Kyung-wha will head up a central disaster and safety countermeasures headquarters, which will aim to ensure smooth dialogue with the victims, families and the tour boat collision.