The U.S. military announced it moved 100 caskets to the demilitarized zone between North and South Korea on Saturday in anticipation of North Korea’s release of the remains of U.S. service members who went missing during the Korean War in the 1950s.

U.S. Forces Korea announced Saturday the wooden “Temporary Transit Cases” had been sent to the DMZ as North Korea prepares to return the remains of fallen American service members who died during the Korean War.

U.S. Forces Korea spokesman Col. Chad Carroll told Fox News the military also sent 158 metal cases to a U.S. airbase outside of Seoul to transfer the remains to the U.S.

South Korean news outlet Yonhap News Agency reported that the cases would be stored in Panmunjom, a border town, for several days before they are sent to North Korea to receive the American remains.

The Defense POW/MIA Accounting Agency, which is tasked with processing the remains and preparing them to be sent home, estimated that 5,300 soldiers who fought in the Korean War had gone missing in North Korea.

The agency added that most service members had been held in prison camps, where it suspects additional remains will be uncovered.

In a June 12 summit with President Trump in Singapore, North Korean leader Kim Jong-un agreed to return the American remains.