Some landed as close as 190 miles from Japan's northwest coast, Japan's defence minister said earlier.

South Korean military and intelligence officials said on Tuesday the four North Korean missiles appeared to be an upgraded version of the Scud type.

North Korea is mired in a separate diplomatic row with Malaysia over the killing of Kim's estranged half-brother at Kuala Lumpur airport last month.

The two countries have expelled each other's ambassador from their capitals and on Tuesday announced tit-for-tat bans on departures of each other's nationals, sharply escalating tensions between two countries that, until the killing of Kim Jong-nam, had maintained rare close ties.

The United States and Japan have requested a United Nations Security Council meeting on the latest North Korean missile launches, which will likely be scheduled for Wednesday, diplomats said.

The planned installation of the US anti-missile defence system has led to a diplomatic standoff between China and South Korea.