Japanese and US government officials have signed an agreement on developing a weapons system to intercept hypersonic missiles.

Hypersonic missiles can fly at about five times the speed of sound, on low and irregular trajectories, making them hard to detect or shoot down.

Russia and China have already deployed such weapons, and North Korea is developing them.

At a summit in August last year, Japan and the United States agreed to jointly develop a missile system capable of intercepting hypersonic missiles.

The deal signed on Wednesday stipulates the assigning of roles and decision-making procedures. The officials say Japan will handle the propulsion device.

Development of the system is planned to begin by the end of March next year, and be completed in the 2030s.

Japan's Defense Ministry says it want to swiftly bolster interception capabilities through Japan-US cooperation as neighboring countries improve their missile-related technologies.