Japanese Prime Minister Kishida Fumio and the commander of the US Indo-Pacific Command have agreed to continue efforts to strengthen the deterrence and response of the Japan-US alliance.

Kishida met Admiral John Aquilino at the prime minister's office in Tokyo on Tuesday to discuss a North Korean ballistic missile launch that took place on the morning of the same day.

They were joined by Chief Cabinet Secretary Matsuno Hirokazu and other officials.

Kishida noted that North Korea has been firing ballistic missiles at an unprecedented pace, having made four launches in the past week alone.

He said Tuesday's launch, which involved a missile flying over Japan, could not be ignored, as it posed a grave and urgent threat to Japan's national security and represented a serious challenge to the international community.

Kishida noted that Japanese and US diplomatic and national security authorities have long been partners, as have US forces in Japan and the Japanese Self-Defense Forces.

He asked the commander to offer his analysis of the situation and his views on how Japan and the US should respond.

They then agreed on the need for continued three-way cooperation among Japan, the US and South Korea, in addition to efforts to strengthen the Japan-US alliance.

Arrangements are being made for Kishida to speak on the phone with US President Joe Biden Tuesday night, Japan time.