South Korea's military said it had "detected one ballistic missile with a medium range or longer fired from the Pyongyang area at 0723 (1023 GMT)".

The missile was fired on a lofted trajectory -- meaning up rather than out, typically done to avoid overflying neighbouring countries -- and "flew 1,000 km (621 miles) before landing in the East Sea," the military said, referring to the body of water also known as the Sea of Japan.

"South Korean and the US intelligence are analysing the specifics," the Joint Chiefs of Staff said, adding they were "maintaining utmost readiness through close coordination with the United States."

Japanese officials earlier confirmed the missile had not fallen within the country's territory and posed no threat to residents.

Climate and environment ministers from the Group of Seven are due to meet this weekend in Sapporo, Hokkaido's regional capital, a month before the group holds its summit in Hiroshima.

The launch is the latest in a string of banned weapons tests conducted by Pyongyang, which has already fired several of its most powerful intercontinental ballistic missiles this year.

It has also tested what its state media has claimed are nuclear-capable underwater drones -- known as Haeil, or tsunami in Korean -- which it says are capable of unleashing a "radioactive tsunami".

On Monday, North Korean leader Kim Jong Un attended a meeting of the Central Military Commission to discuss ways to "cope with the escalating moves of the US imperialists and the south Korean puppet traitors to unleash a war of aggression", Pyongyang's Korean Central News Agency said.

Kim ordered that the country's deterrence capabilities be strengthened with "increasing speed" and in a "more practical and offensive" manner.

- 'Real war' -

Relations between the two Koreas are at one of their lowest points in years, with Pyongyang last year declaring itself an "irreversible" nuclear power, effectively ending the possibility of denuclearisation talks.

Earlier this year, Kim ordered the military to intensify drills to prepare for a "real war".

In response, Washington and Seoul have intensified defence cooperation, staging joint military exercises with advanced stealth jets and high-profile US strategic assets.

North Korea views such exercises as rehearsals for invasion, and on Tuesday described them as "frantic" drills "simulating an all-out war against" Pyongyang.

The latest test was likely a bid by the North "to put pressure on the South and the United States over their joint military exercises," Choi Gi-il, professor of military studies at Sangji University, told AFP.

South Korea on Tuesday also accused North Korea of being "irresponsible" after Pyongyang cut hotline contact with Seoul last week.

North Korea has not answered the twice-daily calls made through a military hotline and an inter-Korean liaison channel since Friday, according to Seoul's unification ministry.

The links were cut a day after Seoul accused Pyongyang of continued unauthorised use of a joint industrial complex in the North Korean city of Kaesong.

South Korea said North Korea had refused to accept its notice demanding that it cease activity at the factory, which was once a symbol of reconciliation.

Seoul pulled out of the venture in 2016 following a North Korean nuclear test, saying the complex was helping to fund Pyongyang's weapons programmes.

"Pyongyang's provocations continue past its protest of US-South Korea defense exercises because Kim Jong-un hasn't finished demonstrating his nuclear delivery capabilities yet," said Leif-Eric Easley, a professor at Ewha University in Seoul.

"However, with the North Koreans literally not answering the phone, the lack of hotlines and diplomacy increases the risk of unintended escalation."