The missile test site North Korean leader Kim Jong-un promised U.S. President Donald Trump to destroy is a large-scale facility in Tongchang-ri, North Pyongan Province.
"Kim promised Trump during their summit on Tuesday to dismantle this facility," a diplomatic source said.
"It's possible that Kim Jong-un, who is well aware of this, told Trump about his plan to dismantle the Tongchang-ri facility to make the U.S. president trust him."
Trump reportedly only started taking an interest in the North Korean nuclear issue after the successful test-launch of the Hwasong-14.
"Kim Jong-un must have won a number of major concessions from Trump in other sectors in return for destroying such a major facility,'" the diplomatic source said.