UNITED NATIONS (AP) – The United States is calling an emergency meeting of the U.N. Security Council for Wednesday following North Korea’s latest test of a ballistic missile that was likely fired from a submarine.

The submarine launch Saturday was another sign of North Korean’s leader Kim Jong Un carrying out his recent vow to speed up development of nuclear weapons.

The United States holds the rotating presidency of the council this month and a spokesperson for the U.S. Mission to the U.N says it called Wednesday’s meeting to discuss the North’s latest launches.

North Korea has fired 15 missiles so far this year, including the country’s first test of an intercontinental ballistic missile since 2017 in March that demonstrated a potential range to reach the entirety of the U.S. mainland.

South Korea’s first underwater-launched ballistic missile was test-fired from a 3,000-ton-class submarine in September 2021.

South Korea’s Joint Chiefs of Staff said the North Korea launch over the weekend occurred from waters near the eastern port city of Sinpo, where North Korea has a major shipyard building submarines.

It said the short-range missile flew 372 miles at a maximum altitude of 37 miles but it didn’t immediately provide details about the submarine that would have been involved in the launch.

South Korean President-elect Yoon Suk Yeol has vowed to take a tougher approach over the North’s nuclear ambitions.

Yoon’s office said in a statement that his government will pursue “actual deterrence ability” against the North’s nuclear and missile threat, but didn’t specify how. Yoon has vowed to strengthen South Korea’s defense in conjunction with its alliance with the United States, which he said would include enhancing missile striking capabilities.

North Korea has been clearly exploiting a favorable environment to push forward its weapons program with the U.N. Security Council divided and effectively paralyzed over Russia’s war on Ukraine. The unusually fast pace in testing activity underscores a brinkmanship aimed at forcing the United States to accept the idea of the North as a nuclear power and remove crippling sanctions, experts say.

There are also signs that North Korea is restoring tunnels at a nuclear testing ground, where it had conducted its sixth and last nuclear test in September 2017, in possible preparations for another explosive test. Analysts say the North could use another nuclear test to claim it can now build small nuclear warheads for its expanding range of shorter-range weapons threatening South Korea and Japan, or put a cluster of bombs on a multi-warhead ICBM.

Jalina Porter, the U.S. State Department’s deputy spokesperson, said during a briefing Friday that the United States assesses that North Korea could be ready to conduct a nuclear test at its Punggye-ri test site as early as this month.