The White House said on Monday that the North Korea issue will be the most important agenda item during U.S. President Joe Biden's trip to South Korea and Japan later this month.

White House spokesperson Jen Psaki revealed the detail during a press briefing when asked about the possibility of a nuclear test by North Korea coinciding with Biden's visit to Seoul.

Psaki said that the U.S. is clearly monitoring the situation, adding that when President Biden visits South Korea and Japan, North Korea will be "front and center in the agenda" especially given the recent tests.

The spokesperson refused to comment on the U.S.' stance on fresh sanctions against North Korea.

Regarding new South Korean President Yoon Suk Yeol, who is expected to take a hawkish stance on China and North Korea, Psaki simply said that President Biden looks forward to having a conversation with Yoon about security in the region and the denuclearization of the Korean Peninsula.