North Korea fired ballistic missiles off its east coast on Friday, South Korea’s military said, a day after South Korea and the US flew powerful fighter jets for a joint drill that the North views as a major security threat.

South Korea’s Joint Chiefs of Staff said the launches were made from the North’s east coast Wonsan region around 3.10pm and the missiles travelled about 300 kilometres (185 miles) before landing in the waters between the Korean Peninsula and Japan.

Japan’s Chief Cabinet Secretary Yoshimasa Hayashi said a North Korean missile landed outside Japan’s exclusive economic zone.

South Korea said its military had bolstered its surveillance posture and was maintaining readiness.

South Korea Koreas Tensions
A TV screen shows a file image of North Korea’s missiles launch during a news programme at the Seoul Railway Station in Seoul, South Korea, on Friday (Ahn Young-joon/AP)

A Joint Chiefs of Staff statement called the launches “a clear provocation” that threatens peace on the Korean Peninsula. It said South Korea will maintain a firm readiness to repel potential aggressions by North Korea in conjunctions with the military alliance with the United States.

North Korea in recent months has maintained an accelerated pace in weapons testing as it continues to expand its military capabilities while diplomacy with the United States and South Korea remained stalled.

Observers say North Korea likely believes an upgraded weapons arsenal would give it leverage to win greater concessions from the US if negotiations resume.

Last week, North Korean leader Kim Jong Un supervised another test firing of a new multiple rocket launch system, according to the North’s state media.

North Korea has maintained it was forced to boost its nuclear and missile programmes to deal with US-led hostility.

North Korea cites the expanded US-South Korean military training that it calls invasion rehearsals.

On Thursday, two South Korean F-35As and two US F-22 Raptors were mobilised for combined aerial exercises over the central region of South Korea. North Korea is extremely sensitive to the deployment of sophisticated US aircraft.

The North’s official Korean Central News Agency (KCNA) said on Friday the redeployment of the US F-22s for joint training with South Korea is “another clear proof of the hostile nature of the US” which seeks “a showdown of force” with North Korea.

KCNA accuses “the military gangsters” of South Korea of intensifying tensions to keep pace with “their master’s confrontation scheme” against the North.

It warned the F-22s flyovers “will only precipitate the advent of a situation that the US does not want to see”. But it did not elaborate on what steps North Korea would take.