President Donald Trump accepted an invitation to meet with North Korean leader Kim Jong Un, the White House said Thursday, a meeting that would mark the first time a serving U.S. president has sat down with the leadership of the heavily militarized and diplomatically isolated country.

The leader-to-leader meeting, which American officials said would take place within the next few months at a location yet to be determined, is a potential turning point after more than six decades of confrontation involving North Korea, its southern...