North Korea announced Wednesday that it had tested a newly developed missile designed to be launched from a submarine, the first such weapons test in two years and one it says will bolster its military’s underwater operational capability.

The test Tuesday was the fifth missile launch since September and came as North Korea steps up pressure on Washington and Seoul to abandon what Pyongyang sees as hostile policies such as joint U.S.-South Korea military drills and international sanctions on the North.

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North Korea’s state-run Korean Central News Agency said the latest test “will greatly contribute to putting the defence technology of the country on a high level and to enhancing the underwater operational capability of our navy.” It said the new missile has introduced advanced control guidance technologies including flank mobility and gliding skip mobility.

The North’s neighbours said Tuesday that they detected the North’s missile firing and said the weapon landed in the waters between the Korean Peninsula and Japan. South Korea’s military described the missile as a short-range, submarine-launched ballistic missile and said the launch was made from waters near the eastern port of Sinpo, where North Korea has a major shipyard building submarines.

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KCNA said Tuesday’s launch was made from “the same 8.24 Yongung ship,” a submarine that North Korea said it used to conduct its first submarine-launched strategic ballistic missile test in 2016. Photos published by North Korea show a missile rising and spewing bright flames above a cloud of smoke from the sea. One image shows the upper parts of what looks like a submarine on the surface of the sea.

Tuesday’s launch is the most high-profile weapons test by North Korea since U.S. President Joe Biden took office in January. The Biden administration has repeatedly said it’s open to resuming nuclear diplomacy with North Korea “anywhere and at any time” without preconditions. The North has so far rebuffed such overtures, saying U.S. hostility remains unchanged.

The launch came days before Sung Kim, Biden’s special envoy on North Korea, was to travel to Seoul to discuss with allies the possibility of reviving diplomacy with Pyongyang.

At a meeting in Washington with his South Korean and Japanese counterparts, Kim emphasized U.S. condemnation of the launch, which violates multiple U.N. Security Council resolutions, and urged Pyongyang to refrain from further provocations and “engage in sustained and substantive dialogue,” the State Department said.

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The U.N. Security Council scheduled emergency closed consultations on North Korea on Wednesday afternoon at the request of the United States and the United Kingdom.

Nuclear negotiations between the U.S. and North Korea have been stalled for more than two years because of disagreements over an easing of crippling U.S.-led sanctions against North Korea in exchange for denuclearization steps by the North.

North Korea has been pushing hard for years to acquire the ability to fire nuclear-armed missiles from submarines, the next key piece in an arsenal that includes a variety of weapons including ones with the potential range to reach American soil.

Acquiring submarine-launched missiles would be a worrying development because that would make it harder for the North’s rivals to detect launches and provide the country with retaliatory attack capability. Still, experts say it would take years, large amounts of resources and major technological improvements for the heavily sanctioned nation to build at least several submarines that could travel quietly in seas and reliably execute strikes.

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North Korea last tested a submarine-launched ballistic missile in October 2019.

In a report this month on North Korea’s military capabilities, the U.S. Defense Intelligence Agency said the North’s pursuit of submarine-launched ballistic missile capabilities along with its steady development of land-based mobile long-range weapons highlight Pyongyang’s intentions to “build a survivable, reliable nuclear delivery capability.”