AMMAN (Reuters) - Rescuers combed the shores of Jordan’s Dead Sea early on Friday, searching for survivors, after flash floods killed at least 21 people, most of them school children in a bus that was swept away.

The floods, which followed torrential rain, poured through valleys and deep ravines sweeping people, vehicles and livestock to the shores of the Dead Sea, the lowest point on earth.

Thirty-seven people were rescued in a major operation involving helicopters and divers, civil defense sources said. Rescue operations continued for other possible survivors.

The school bus that was swept away carried 44 children and teachers who were on a school picnic trip in the popular tourist spot, police chief Brigadier General Farid al Sharaa told state television.

The majority of dead were schoolchildren. The dead also included three Iraqis and a 20-year-old woman who was with the children on the school bus, a civil defense source said.

King Abdullah described the disaster as a “huge tragedy that hurt all of us” and the national flag was lowered in mourning as public opinion and politicians began raising questions in local media outlets about the preparedness of emergencies services to cope with such a disaster.

Prime Minister Omar Razzaz said it appeared the school had broken regulations by going ahead with the trip, which had been banned in the Dead Sea area because of bad weather. He also called for an investigation into infrastructure in the area.

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Health Minister Ghazi al Zibn said most of the injured had left the hospital in the area near the Dead Sea. At least eight people were still missing, a medical source said.

A bridge on one of the cliffs of the Dead Sea collapsed under the force of the rains, the first such after the end of summer.

Neighboring Israel sent search-and-rescue helicopters to assist, an Israeli military statement said. The team, dispatched at Amman’s request, was operating on the Jordanian side of the Dead Sea.

A Jordanian official said Israel had offered to help and the kingdom requested a helicopter with the technology to find buried bodies in mud that would accelerate the searches.

The kingdom, which shares the longest border with Israel and have a common peace treaty, has a long a history of cooperation with its neighbor in natural disasters.

Jordan helped Israel in 2016 with fire-fighting equipment after a rash of fires that burned for days, straining Israel firefighters.

An Israeli helicopter pilot who participated in the search said that close to 10 Israeli aircraft and drones had been deployed.