North Korea's top negotiator will reportedly carry a letter from leader Kim Jong-un to U.S. President Donald Trump when he travels to Washington this week.

CNN international correspondent Will Ripley wrote in a tweet on Wednesday that a source familiar with U.S.-North Korea denuclearization talks told him ex-spy chief Kim Yong-chol will be carrying a letter from his leader when he arrives in Washington on Thursday. 

Ripley also tweeted that Kim's delegation has no plans to visit the North Korean mission to the United Nations in New York, "indicating a high level of secrecy surrounding the trip." He added that details were kept secret even from North Korean diplomats posted in the U.S.

CNN earlier reported that Kim plans to arrive in Washington Thursday for a two-day stay, and he is expected to hold talks with Secretary of State Mike Pompeo on details of a planned summit between their leaders. 

It also said a letter from Trump was hand-delivered to the North Korean leader in Pyongyang over the weekend.