One of North Korea's top negotiators is on his way to Washington to meet US officials ahead of a possible second summit between Kim Jong-un and US President Donald Trump. South Korean reports say that Kim Yong-chol, flying from Beijing, is carrying another letter from Mr Kim to Mr Trump. <br />''<br />''South Korea's Yonhap news agency said, he is expected to meet US Secretary of State Mike Pompeo today. Speculation is mounting that the second summit could be held in Vietnam. <br />''<br />''<span style="color: #222222;">Little progress has been made on North Korean de-nuclearisation since a historic meeting in Singapore last June between Mr Kim and Mr Trump. Mr Kim visited China earlier this month for talks with President Xi Jinping, as he did before the Singapore summit. </span>