The US Contingent will take part in the jamboree program on Saturday before moving to U.S. Army Garrison Humphreys near the jamboree site on the following day, according to an email obtained by Reuters.

"The US Contingent to the World Scout Jamboree has made the difficult decision that we will be departing the 25th World Scout Jamboree site early because of ongoing extreme weather and resulting conditions at the jamboree site," said the email sent out to parents by the US Contingent Media Team.

Temperatures have hit 34 Celsius (93F) in Saemangeum, near the city of Buan on South Korea's west coast, where 39,000 participants, mostly scouts aged 14-18, are camping.

The pullout by the United States comes as a further blow to the organizers and the South Korean government, which on Friday had said it would send more water trucks, air-conditioned spaces and medics to save the event.

Scouts from Britain, the largest grouping at the jamboree, said on Friday they were moving to hotels in Seoul for the rest of their stay, to alleviate pressure on the site.

The World Organization of the Scout Movement also said in a statement on Friday that it had asked the Korean Scout Association to consider "alternative options to end the event earlier than scheduled and support the participants until they depart for their home countries."

President Yoon Suk Yeol called a cabinet meeting to approve spending 6 billion won ($4.6 million) to support the jamboree, and Prime Minister Han Duck-soo said the government would "use all its resources to ensure that the jamboree can end safely".

Hit by extreme heat, hundreds of participants at the event fell ill and were treated for heat-related ailments, prompting complaints from parents over the safety of their children.

More than 150 countries were taking part in the gathering as of Friday, according to officials.

The jamboree is scheduled to run until Aug. 12.