US heavy bombers and stealth jet fighters took part in a joint live fire drill in South Korea on Thursday, intended as a show of force against the North after its latest missile launch, Seoul said.

"South Korean and US air forces conducted an air interdiction exercise in order to strongly cope with North Korea's repeated firing of ballistic missiles and development of nuclear weapons," the South's air force said in a statement.

Two B-1B "Lancer" bombers from Guam and four F-35B stealth jet fighters from the Marine Corps' Iwakuni airbase in Japan conducted the drill, with four South Korean jet fighters also taking part.

B-1B overflights of the peninsula from Guam, a US territory in the Pacific, infuriate the North, which cited them when it announced a plan to fire a salvo of missiles towards the island.

It was one of the moves that saw tensions spiral this month, including a new set of UN Security Council sanctions, US President Donald Trump's apocalyptic warning to rain "fire and fury" on Pyongyang, and culminated with the North firing a missile over Japan on Tuesday.

The drill took place at the Pilseung shooting range in Gangwon province, some 150 kilometres (94 miles) south of the Demilitarized Zone dividing the two Koreas.

A South Korean airforce spokesman said it was separate from the annual Ulchi Freedom Guardian joint exercises, which wrapped up on Thursday.

Tens of thousands of South Korean and US troops took part in the largely computer-simulated exercise that ran for two weeks in the South.

The annual drills are viewed by nuclear-armed Pyongyang as a highly provocative rehearsal for invasion, and it always meets them with threats of strong military counteraction.

The North's state media called the Hwasong-12 intermediate range missile flight over northern Japan "a part of the muscle-flexing" against the war games.

Leader Kim Jong-Un called for more launches into the Pacific, the KCNA news agency said.

North Korea says it needs nuclear weapons to protect itself against the US and analysts say Pyongyang has made rapid strides in its ballistic technology in defiance of seven sets of United Nations resolutions.

In July it conducted two successful ICBM launches which appeared to bring most of the US mainland into range.