TOKYO (THE JAPAN NEWS/ ASIA NEWS NETWORK) - Every time North Korea test-fires a ballistic missile, which can be used as a nuclear warhead delivery vehicle, its nuclear capabilities get stronger and the threat it poses gets more serious.

Japan, the United States and South Korea should make efforts to strengthen their cooperation to improve deterrence. North Korea fired a ballistic missile into the Sea of Japan. It flew about 500 km and fell outside Japan's exclusive economic zone.

It is believed to have reached an altitude of about 800 km, having been launched at a higher angle than the normal trajectory. This is North Korea's 13th missile launch this year. It is likely that Pyongyang is trying to confirm and improve the performance of its missiles by frequently launching a wide variety of them. It has also been developing new types of missiles, including a hypersonic missile that flies on irregular trajectories.

Some say that the latest launch is a test toward the completion of an intercontinental ballistic missile (ICBM) that can reach the US mainland. Japan, the United States and South Korea must quickly analysee the available information.

North Korea showed off its various missiles, including a new ICBM - the Hwasong-17 missile - at its military parade marking the 90th anniversary of the founding of its military on April 25.

North Korean leader Kim Jong Un, who is also general secretary of the Workers' Party of Korea, said in a speech on the occasion that he would strengthen and develop his arsenal at the "fastest possible pace."

North Korea's selfish logic is to possess nuclear weapons to deter attacks from the United States. Pyongyang is believed to be working on the construction of a test site for not only missile tests, but also resumed nuclear tests. More caution is needed.

Kim has also stated he will not hesitate to put nuclear weapons to practical use. Was Kim inspired by Russian President Vladimir Putin, who has threatened to use nuclear weapons in connection with his invasion of Ukraine?

Any behaviour that makes light of the threat of nuclear war - capable of wiping out humankind - is unacceptable. The latest launch comes just before South Korean President-elect Yoon Suk-yeol takes office on May 10.

Yoon has indicated that he will change the current administration's conciliatory policy toward North Korea and strengthen the defence system through close cooperation with the United States and Japan. The launch was also apparently intended to threaten Yoon.

US President Joe Biden is scheduled to visit Japan and South Korea in late May. It is hoped that the United States will reaffirm the strength of its alliances with Japan and South Korea.

Despite North Korea's launches of ballistic missiles in violation of UN Security Council sanctions resolutions, the council has not taken any effective action against them. The United States is preparing a new resolution to strengthen sanctions against North Korea, but it is unlikely to be adopted as long as China and Russia, who hold veto power as permanent members of the UN Security Council, oppose it.

China, which backs North Korea, needs to face up to the reality that the Security Council's failure to take any action has allowed Pyongyang to run out of control. China also must accept tougher sanctions against North Korea.

• The paper is a member of The Straits Times media partner Asia News Network, an alliance of 23 news media organisations.