SEOUL >> North Korea conducted a rare test of a submarine-launched ballistic missile over the weekend, but it ended in failure, said a South Korean lawmaker who attended a closed-door parliamentary briefing by the National Intelligence Service on Monday.

Joo Ho-young, a governing party lawmaker and chairman of the National Assembly’s Intelligence Committee, cited officials from the intelligence service, the South’s main spy agency, as saying that North Korea had conducted the test on Saturday off Wonsan, a port city east of Pyongyang, with its leader, Kim Jong Un, watching.

But there was no sign that the missile was successfully ejected from the submarine and took off, Joo told reporters after the intelligence officials briefed his committee. No rocket trajectory was detected, and what appeared to be debris from a missile was later seen floating on the surface of the sea, he said.

The intelligence service declined to comment on the closed-door parliamentary session.

On Monday, Kim Min-seok, the main spokesman for the Defense Ministry of South Korea, declined to provide details, saying that information related to “the North’s launching of an SLBM,” or submarine-launched ballistic missile, remained classified.

“What we can say is that North Korea is continuing the development and testing of an SLBM,” Kim said. “It is a violation of United Nations Security Council resolutions banning it from developing or testing ballistic missiles.”

Fears in the South of North Korean missile threats have grown since May, when the North claimed that it had successfully test-fired such a weapon and released photographs of Kim observing a missile soaring out of the water.

Some missile experts have since questioned the claim, however, saying that the photographs appeared to have been modified. They said that the North was probably still many years away from developing a submarine-launched ballistic missile, which would present a hard-to-detect danger for its enemies in the region. But South Korean officials maintained that the North had successfully fired a submarine-launched missile, which flew nearly 500 feet before falling into the sea. They said they expected more such tests.

As it vowed to counter the North’s growing missile threat, South Korea said in June that it had successfully test-fired its first ballistic missile with a range great enough to hit any part of North Korea. The South’s president, Park Geun-hye, was said to have watched that test.