North Korea on Saturday warned Japanese Prime Minister Shinzo Abe that he could soon see a "real ballistic missile" while excoriating him as the "most stupid man ever known in history".

Iran plans to boost its ballistic and cruise missile capacity and acquire modern fighter planes and submarines, the Iranian state news agency IRNA quoted a senior Defence Ministry official as saying on Saturday.

Saudi air defences on Tuesday intercepted a ballistic missile fired from rebel-held territory in neighbouring Yemen, state media reported, as a Riyadh-led military coalition intensifies an offensive to capture a strategic port.

Saudi air defences on Tuesday intercepted a ballistic missile that targeted the western city of Yanbu after being fired from rebel-held territory in neighbouring Yemen, a Saudi-led military coalition said.

Donald Trump says that unless European allies rectify "flaws" in Tehran's deal with world powers by May 12 he will refuse to extend US sanctions relief for Iran.

Saudi Arabia's air defence forces intercepted at least three ballistic missiles fired at Saudi cities by Yemen's Houthis, who claimed to have targeted the defence ministry in Riyadh and a Saudi Aramco distribution facility in Najran on Wednesday.

An alert warning of an incoming ballistic missile aimed at Hawaii was sent in error Saturday, sowing panic and confusion across the US state -- which is already on edge over the risk of attack -- before officials dubbed it a "false alarm."

Saudi air defences intercepted a ballistic missile fired towards the capital Riyadh on Tuesday, the Saudi-led coalition said, the latest attack by a Yemeni group that could escalate a proxy war between the kingdom and regional rival Tehran.

South Korean President Moon Jae-In will visit China next week for talks on North Korea and other issues, amid tentative signs of diplomatic movement after months of high tensions over Pyongyang's nuclear and missile threats.

North Korea has conducted a flurry of missile tests this year in defiance of repeated international protests, including from aviation authorities.

The five-day Vigilant Ace drill -- involving 230 aircraft, including F-22 Raptor stealth jet fighters, and tens of thousands of troops -- began on Monday morning, Seoul's air force said.

North Korea on Sunday blasted the United States and South Korea as "warmongers" on the eve of their largest-ever joint air exercise, saying it could trigger a nuclear war.