Jordan's flash floods killed at least 18 people and injured at least 35 others, mostly middle school children, near the Dead Sea on Thursday.

Heavy rains washed away a bus carrying 44 students and teachers during a picnic trip at the tourist attraction. Families picnicking at the location also fell victims to the floods. 

A major rescue operation to find survivors was launched, with the number of missing individuals still unknown, according to hospital sources who spoke to Reuters.  

The Dead Sea shore is the Earth's lowest point on dry land which makes it vulnerable to flash flooding when rain water rushes down its deep canyons.

The bus was headed to the Zarqa Ma'in hot springs area, despite the fact that the Ministry of Education banned trips to the Dead Sea due to the weather conditions, according to Prime Minister Omar Razzaz.

Thursday's floods surged for up to five kilometers, sweeping the bus into a valley. 

Police chief Brigadier General Farid Al-Sharaa said the floods "swept away the students for four to five kilometers," some as far as the Dead Sea, adding that some victims saved themselves by holding onto rocks, Time reported.

In response, authorities launched a rescue operation involving boats, helicopters, and marine divers, rescuing at least 34 people, some of whom are in critical conditions.

The Israeli Air Force said it dispatched helicopters and soldiers to assist in the operation at the request of the Jordanian Government.

With the death toll on the rise, Jordanian King Abdullah bin Al-Hussein cancelled his trip to Bahrain which was scheduled for Friday. 

People from across the world, including Arab leaders, took to social media to express their condolences to those affected: 

"Their tragedy is our tragedy"

"Our hearts sympathize with our family in Jordan. Their tragedy is our tragedy, after a bus was swept away due to flooding. Their children are our children. May they rest in peace. From a school bus to the doors of heaven, may God have mercy on them. My sincere condolences to the Jordanian people."

People are sending messages of support to the victims' families

"There are no words"

Twitter users from different nationalities expressed their sympathies

"Pray for Jordan"

"A sad day in our national memory"