The Japanese government showed "understanding" of U.S. President Donald Trump's decision to cancel his planned summit with North Korean leader Kim Jong Un in Singapore next month, while pledging to keep maximum pressure on Pyongyang to foil its nuclear and missile development.

"The important thing is not holding a meeting itself but becoming an opportunity to move toward the solution of the nuclear and missile issues as well as the abduction issue," Chief Cabinet Secretary Yoshihide Suga told a press conference.

"Japan, the United States and South Korea will continue to put pressure on North Korea to change its policy," the top government spokesman said, adding that Tokyo will remain vigilant and closely monitor the situation.

(Chief Cabinet Secretary Yoshihide Suga)

Japan had hoped for a breakthrough toward the denuclearization of the Korean Peninsula at what would have been the first-ever U.S.-North Korea summit on June 12. It had also urged Washington to take up the issue of the abduction of Japanese citizens by North Korea in the 1970s and 1980s at the talks.

Speaking to reporters, Defense Minister Itsunori Onodera also said Japan will keep applying pressure on Pyongyang, including monitoring the North's ship-to-ship cargo transfers.

"Japan will closely collaborate with the United States and South Korea to push North Korea to take concrete actions toward the complete abandonment of weapons of mass destruction and ballistic missiles," he said.

Meanwhile, Foreign Minister Taro Kono, who is on a visit to Mexico, showed "understanding" of the U.S. decision to call off the gathering, saying, "It is meaningless to hold a summit if it does not bring about progress."

But Kono expressed his intention to continue to call for a summit between Washington and Pyongyang. "To achieve the North's denuclearization and solve the abduction issues, Japan will closely work with the United States," he said.

In cancelling the summit, Trump cited, in a letter to Kim, "tremendous anger and open hostility" in a recent statement released by North Korea. "I feel it is inappropriate, at this time, to have this long-planned meeting," the U.S. president said.

North Korea had recently warned that it might cancel the summit, lambasting ongoing joint military drills by South Korea and the United States as well as Washington's call for Pyongyang to unilaterally abandon its nuclear weapons.

Japanese Prime Minister Shinzo Abe, who is on a visit to Russia, is expected to issue a comment on the cancellation of the summit later.