SEOUL • A North Korean launch of a ballistic missile from a submarine that appears to have failed underscores the technological limitations of the isolated country's weapons programme.

The launch was made around 2.30pm local time last Saturday in the sea between the Korean peninsula and Japan, with debris in the water indicating it failed, South Korea's Yonhap news agency reported, citing an unidentified South Korean government official.

South Korean Defence Ministry spokesman Kim Min Seok declined to confirm the report.

"The North appears to have failed in its launch," said the official on condition of anonymity, according to Yonhap. "The missile was not seen flying in the air; only debris from its coverings was spotted."

The attempt, if confirmed, signals that North Korea is determined to advance its military capabilities following another launch in May this year of a submarine-launched ballistic missile, which Pyongyang boasted as a success, but has not been verified independently.

Even so, the test launch in May fuelled alarm in South Korea and the United States about the possibility of advances in the military capabilities of a state that is pursuing a nuclear weapons programme.

"North Korea is never going to stop," said Mr Kim Soo Am, a researcher at the Korea Institute for National Unification. "North Korea has already advertised its leader supervising the missile test. Even if they have failed to successfully launch it today, it is telling the world it will keep going with weapons development."

In September, the country said it was ready to use nuclear weapons against the US at any time and that its main nuclear facility was fully operational. The US and South Korea responded with a joint plan that enables the two countries to detect, disrupt and destroy North Korean missiles if needed.

North Korea is banned from testing ballistic missiles under the United Nations Security Council resolutions imposed over its nuclear tests and long-range rockets.

South Korea estimates North Korea has 2,500 to 5,000 tonnes of chemical weapons. The regime conducted its third nuclear test in 2013 and threatened this year to conduct a fourth one.

North Korea has defied UN sanctions for its missile and nuclear tests and is believed to be developing a nuclear device small enough to be mounted on a ballistic missile. It is believed to be some years away from perfecting the technology.

The Koreas are technically still at war after their 1950 to 1953 conflict ended in a truce, not a peace treaty.

BLOOMBERG, REUTERS, AGENCE FRANCE-PRESSE