Japan's policy on North Korea is under growing scrutiny, particularly since Prime Minister Shinzo Abe expressed willingness to hold a summit with North Korean leader Kim Jong Un "without conditions."

Since Pyongyang fired projectiles that appeared to be short-range ballistic missiles on May 4 and 9, Japan has taken a tougher stance against North Korea than the United States, claiming that the missile and nuclear threats remain unchanged in the region.

Some Japanese government officials, however, have become concerned that as long as Tokyo continues to present a strong front against Pyongyang, a summit between Abe and Workers' Party of Korea Chairman Kim will not materialize.