The US-led United Nations Command had stored the boxes at the border village of Panmunjom for weeks.

If the North returns the remains, it would be a concrete measure to follow up on the Singapore summit deal between President Donald Trump and the North's leader Kim Jong-un.

It would represent another feat for Trump and could be conducive to building mutual trust and stimulate the slow-moving denuclearization process.

Earlier this week, CNN reported that a group of US Defense Department officials is expected to visit South Korea soon to assist with the remains return.

They apparently include representatives from the Defense POW/MIA Accounting Agency, who will likely travel to the North for an initial inspection.

The US is planning to pick up the remains at the North's Kalma Airport along its east coast and move them to Osan Air Base, south of Seoul, by plane, where a ceremony is to take place, according to the source.

The remains will then be airlifted to a forensic lab in Hawaii.

The North and the US had military talks on the remains issue at Panmunjom earlier this month. (Yonhap)