South Korea's top national security adviser made another secret visit to the United States on Thursday, sources said, ahead of a high-stakes summit between the U.S. and North Korean leaders.
Chung Eui-yong, chief of the presidential National Security Office, arrived in Washington possibly to meet with his U.S. counterpart, National Security Adviser John Bolton, according to multiple diplomatic sources.
The White House did not respond to a Yonhap request for confirmation.
Chung's visit comes ahead of a planned meeting between U.S. President Donald Trump and North Korean leader Kim Jong-un in late May or early June.
The summit will be closely watched after South Korean President Moon Jae-in and Kim agreed in their own meeting last week to pursue "complete denuclearization" of the Korean Peninsula.
Trump has said he will be going into the negotiations aiming to get rid of the regime's nuclear weapons.
An announcement on the date and location of the first-ever U.S.-North Korea summit is expected to come in the next few days after Trump hinted at the possibility of meeting Kim in the Demilitarized Zone dividing the Koreas.
Chung traveled to Washington in early March after meeting Kim in Pyongyang to convey the North Korean leader's wish to meet with Trump and his willingness to discuss the denuclearization of the regime.
Trump and Kim exchanged threats and personal insults last year as North Korea tested its nuclear weapons and ballistic missile programs.
The South Korean official is in Washington for his third known visit since Bolton took office last month. (Yonhap)