North Korea fired a ballistic missile from the sea on Wednesday, South Korea’s military said, a suggestion it may have tested an underwater-launched missile for the first time in three years ahead of a resumption of nuclear talks with the United States this weekend.

South Korean military radars detected the missile flying about 450 kilometres at a maximum altitude of 910 kilometres after liftoff from a site about 17 kilometres off the North’s eastern coastal town of Wonsan, about 250 kilometres east of the capital Pyongyang, Defence Minister Jeong Kyeong-doo told lawmakers.

Jeong said he believes the missile’s actual range is longer because North Korea appears to have deliberately elevated its altitude. In the past, North Korea often fired missiles at a lofted angle to avoid neighbouring countries. Some experts say the weapon fired Wednesday is a medium-range missile, which North Korea stopped firing along with long-range missiles after it entered into talks with the U.S. early last year.

Japan lodged an immediate protest against North Korea, saying the missile landed inside Japan’s economic exclusive zone. If confirmed, it would be the first North Korean missile that has landed that close to Japan since November 2017.

The U.S. State Department called on North Korea “to refrain from provocations, abide by their obligations under UN Security Council resolutions, and remain engaged in substantive and sustained negotiations to do their part to ensure peace and stability on the Korean Peninsula and achieve denuclearization.”

South Korean military officials wouldn’t officially disclose whether the missile was fired from a submarine, a barge or another possible platform. But during an emergency National Security Council meeting, council members placed weight on the possibility that North Korea performed a submarine-launched missile test and expressed “strong concerns” over the North Korean move, according to South Korea’s presidential office.

North Korea having the ability to launch missiles from submarines would be alarming because such weapons are harder to detect in advance. Some experts say the North is attempting to raise the stakes and ramp up pressure on the United States before their nuclear negotiators meet on Saturday.

“The North is trying not convey a message that time is not on the side of the United States and that it could take a different path if the working-level talks don’t go the way it wanted,” said Cha Du-hyeogn​​​​​, a visiting scholar at Seoul’s Asan Institute for Policy Studies.

The Joint Chiefs of Staff statement said the weapon fired Tuesday is believed to be a “Pukguksong-class” missile. It refers to a solid-fuel missile that North Korea tested-launched from an underwater test platform in 2016, with the hope that it could eventually be a part of its submarine weaponry. That missile flew 500 kilometres, and North Korean leader Kim Jong-un said at the time that his country had gained “perfect nuclear-attack capability.”

If fired at a standard trajectory, the missile could have travelled 1,500 to 2,000 kilometres, said Kim Dong-yub, an analyst from Seoul’s Institute for Far Eastern Studies.

North Korea has been trying to obtain the ability to fire ballistic missiles from submarines, though the tests needed for that appear to have been put off while it has been engaged in nuclear diplomacy with the United States since early last year.

North Korea, under Kim Jong-un, has been working toward the capability of launching ballistic missiles from submarines. (Athit Perawongmetha/Reuters)

When the North’s news agency in July publicized photos of a newly built submarine and said its operational deployment “is near at hand,” some outside experts said it was North Korea’s biggest submarine with several launch tubes for missiles. An estimated 70 other submarines possessed by North Korea only have launch tubes for torpedoes, not missiles, according to the experts.

Cha said flight data provided by South Korea’s Joint Chiefs of Staff suggested that it was more likely that the North tested the same type of missile it fired in 2016, instead of a new weapons system.

South Korea’s Defence Ministry also declined to confirm whether it was a medium-range missile. But it said it flew higher than any other short-range weapons the North fired in previous 10 rounds of launches since May.

U.S. President Donald Trump has downplayed the significance of recent short-range launches by North Korea, but it’s unclear whether he would do the same this time.

Japan condemns launch

Japan also confirmed the North Korean missile launch. It earlier said North Korea fired two missiles, but later corrected itself and said there had been a single launch and perhaps the missile broke into two parts.

Japanese Defence Minister Taro Kono said the missile fell inside Japan’s exclusive economic zone. He called the launch “a serious threat to Japanese national security.” Kono also said the launch without an advance warning was an “extremely problematic and dangerous act” for the safety of vessels and aircraft.

Kono declined to say whether it was a submarine-launched missile.

Japanese Prime Minister Shinzo Abe condemned the launch and said it violated UN resolutions that ban North Korea from conducting any launch using ballistic technology.

“We will continue to co-operate with the U.S. and the international community and do the utmost to maintain and protect the safety of the people as we stay on alert,” Abe said.

The launch may also be seen as a way for North Korea to express its displeasure over South Korea displaying for the first time some of its newly purchased U.S.-made F-35 stealth fighter jets at its Armed Forces Day ceremony on Tuesday. The North has called the F-35 purchases a grave provocation that violate recent inter-Korean agreements aimed at lowering military tensions.

Cha stressed the North Korean launch demonstrated its expanding ability to strike allies South Korea and Japan, not the U.S. mainland.

North Korea has been maintaining its self-imposed moratorium on nuclear and long-range missile tests since Kim began diplomacy with Trump.

But since his second summit with Trump in Vietnam in February collapsed without reaching any agreement, Kim has hinted at scrapping that weapons test moratorium and has demanded Trump come up with mutually acceptable new proposals by December. In Hanoi, Trump rejected Kim’s calls for broad sanctions relief in exchange for partially surrendering its nuclear capabilities.

Tuesday’s launch, the North’s ninth round of weapons tests since late July, came hours after Choe Son-hui, North Korea’s first vice-minister of foreign affairs, said North Korea and the United States have agreed to resume working-level nuclear negotiations on Saturday following a preliminary contact on Friday.

U.S. State Department spokesperson Morgan Ortagus, who is travelling with Secretary of State Mike Pompeo in Rome, confirmed U.S. and North Korean officials plan to meet within the next week.

Both North Korea and the U.S. didn’t say where the weekend meetings would take place.