SEOUL, South Korea (AP) — South Korea is preparing to evacuate tens of thousands of scouts from a coastal jamboree site as Tropical Storm Khanun looms, scouting officials said Monday.

The World Organization of the Scout Movement said it received confirmation from South Korea’s government of the early departure for all participants in the southwestern county of Buan. That means quickly moving tens of thousands of scouts — mostly teenagers — from 158 countries out of the storm’s path.

South Korea’s weather agency reported that Khanun was about 330 kilometers (205 miles) northeast of the Japanese island of Okinawa as of 9 a.m. Monday. It was expected to make landfall in South Korea on Thursday morning, packing high winds. Large swaths of the country’s south, including Buan, could be affected by the storm as early as Wednesday, the agency said.

President Yoon Suk Yeol’s office said he called for “contingency” plans, which could include relocating them to hotels and other facilities in the country’s capital, Seoul, and nearby metropolitan areas.

Hot temperatures have already forced thousands of British and American scouts to leave the site, which is made on land reclaimed from sea. Hundreds of participants had been treated for heat-related ailments since the jamboree started on Wednesday. Long before the event’s start, critics raised concerns about bringing such large numbers of young people to a vast, treeless area lacking protection from the summer heat.

Organizers earlier on Monday were scurrying to come up with plans to evacuate the scouts ahead of the storm’s arrival. Choi Chang-haeng, secretary-general of the jamboree’s organizing committee, said organizers have secured more than 340 evacuation venues, including community centers and gyms, in regions near Buan.

About 40,000 scouts — mostly teenagers — from 158 countries came to the jamboree, built on land reclaimed from the sea. About 4,500 were from the U.K., representing the largest national contingent, while about 1,000 were from the United States.