With only five days ahead of the second U.S.-North Korea summit in Hanoi, the chief envoys from the two sides continued their final round of working-level negotiations in the Vietnamese capital.

Reports from Hanoi said a North Korean delegation led by special envoy Kim Hyok-chol was seen entering the U.S. delegation's hotel at around 11:00 a.m. on Friday.

Kim and his American counterpart Stephen Biegun held a four-and-a-half-hour meeting at the same hotel the day before.

While details of the ongoing negotiations have not been disclosed, Biegun and Kim are expected to fine-tune details for a summit declaration, including the North's steps for denuclearization and establishing peace on the Korean Peninsula.

The envoys will also likely negotiate what the U.S. can offer in return for the North's denuclearization efforts.

Meanwhile, South Korea's chief nuclear envoy Lee Do-hoon departed for Hanoi on Friday, where he plans to meet Biegun to consult on a strategy for next week's summit.