North Korea's top envoy Kim Yong Chol involved in talks with the US arrived in Beijing on Thursday and is thought to visit Washington.

Kim Yong Chol would be carrying a new letter from Kim Jong Un to Trump in Washington, Reuters reported.

The envoy will deliver the letter during the talks in Washington on Friday, the source said without elaborating.

The first ever summit of US and North Korean leaders was held in Singapore on June 12, 2018. The US President Donald Trump and North Korean leader Kim Jong-un adopted a joint statement. Thus, Pyongyang expressed its readiness for complete denuclearization, and the US pledged to provide security guarantees to the North Korea.

Earlier on December, Trump said his next meeting with Kim Jong-un may be scheduled for January or February 2019.