North Korea fired two short-range ballistic missiles toward the sea off its east coast on Saturday, marking its fourth launch in a week.

South Korean, Japanese and US militaries said they detected the two launches, with estimates indicating they flew between 220 and 250 miles before landing in waters between Japan and the Korean peninsula.

Pyongyang’s launch follows a continuation of a regional arms race between the Koreas, which has seen a major increase in weapons and military spending.

Japan’s vice defence minister, Toshiro Ino, said the missiles showed “irregular” trajectory, while some observers said the weapons reported low and “irregular” trajectory – suggesting they were likely nuclear-capable missiles modelled after Russia’s Iskander missile.

The test launch is seen as a response to recent naval drills between South Korea and the United States, which also involved Japan.

It came just before South Korea staged a large military show, displaying advanced weaponry, where the country’s president Yoon Suk-yeol condemned what he called recent military provocations by the North and vowed to strengthen joint military drills with the US.

Nuclear tests and ballistic missile launches by North Korea have long been banned by the UN Security Council.

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On Friday, South Korea, the US and Japan held their first trilateral anti-submarine drills in five years off the Korean Peninsula’s east coast.

While earlier this week, US vice president Kamala Harris visited South Korea, meeting with Mr Yoon in Seoul on Thursday.

Mr Yoon said North Korea’s “obsession” with nuclear weapons is deepening the suffering of its own people and warned of an “overwhelming response” from South Korean and US officials should such weapons be used.

North Korea views such military exercises by the allies as an invasion rehearsal and argues they reveal US and South Korean “double standards” because they brand the North’s weapons tests as a provocation.

Analysts say North Korea’s increased pace of testing can be seen as an effort to build operational weapons, as well as to take advantage of a world distracted by the Ukraine conflict and other crises to “normalise” its tests.

Leif-Eric Easley, a professor at Ewha University in Seoul, said: “Despite North Korea’s internal weaknesses and international isolation, it is rapidly modernising weapons and taking advantage of a world divided by US-China rivalry and Russia’s annexation of more Ukrainian territory.”

This year, North Korea performed missile tests more than 20 times, a record number, as it refuses to resume long-stalled nuclear talks with the United States.