U.S. National Security Adviser John Bolton takes notes during a meeting between U.S. President Donald Trump and China's Vice Premier Liu He in the Oval Office at the White House in Washington, U.S., Friday (local time). Reuters-Yonhap

U.S. National Security Advisor John Bolton has canceled a planned visit to South Korea ahead of next week's summit between U.S. President Donald Trump and North Korean leader Kim Jong-un, a White House spokesman said Friday (local time).

"Ambassador Bolton has canceled his travel to the Republic of Korea to focus on events in Venezuela," the National Security Council spokesman told Yonhap News Agency on condition of anonymity

A diplomatic source in Seoul earlier told Yonhap, "The White House has said that he will not visit Seoul due to the need to watch the Venezuelan situation."

On Wednesday, CNN reported, quoting two U.S. officials, that he will visit South Korea this week for discussions about the upcoming summit between Trump and Kim set for Feb. 27 and 28 in Hanoi, Vietnam.