The chief nuclear envoy of the Republic of Korea (ROK) headed to Hanoi on Friday for consultations on next week's summit between the Democratic People's Republic of Korea (DPRK) and the United States, according to Yonhap.

Lee Do-hoon, special representative for Korean Peninsula Peace and Security Affairs, plans to meet and discuss a negotiation strategy with Stephen Biegun, Washington's envoy for Pyongyang, said Yonhap, citing a government source.

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Biegun is in charge of the agenda for the two-day DPRK-U.S. working-level negotiations that are expected to start on Wednesday between DPRK leader Kim Jong Un and U.S. President Donald Trump.

Biegun on Thursday spent several hours meeting with his DPRK counterpart, Kim Hyok Chol. More discussions on a joint statement after the Trump-Kim summit are expected to be held between the two.

Kim may arrive in Vietnam by train

Ahead of the second Trump-Kim summit, a hotel near the China-DPRK border reportedly stopped receiving bookings, suggesting Kim may take a train journey to Hanoi, for the summit.

The hotel, named Zhonglian, is located in the border city of Dandong near the China-DPRK Friendship Bridge. It has stopped accepting bookings in the past when the DPRK leader has traveled to China by train, said Yonhap.

Kim Chang Son, a member of the State Affairs Commission of the DPRK, also known as the leader's "butler," reportedly inspected a rail station in Lang Son, a border city of China and Vietnam on Sunday.

(Cover: U.S. special representative for DPRK Stephen Biegun (R), shakes hands with the ROK's Special Representative for Korean Peninsula Peace and Security Affairs Lee Do-hoon (L) prior to their meeting at the Foreign Ministry in Seoul, ROK, February 9, 2019. /VCG Photo)