North Korea’s leader Kim Jong Un oversaw the test-launch from a location off-shore as the submarine dove under water and “a ballistic missile surfaced from the sea and soared into the air, leaving a fiery trail of blaze,” the official KCNA news agency said.

“Through the test, it was verified and confirmed that the underwater ballistic missile launch from a strategic submarine fully achieved the latest military, scientific and technical requirements,” KCNA said.

North Korea is under United Nations sanctions banning it from developing or using ballistic missile technology .

The report did not mention the date or the exact location of the test, but a separate KCNA dispatch on May 9, said Kim gave field guidance at a fishery complex in Sinpo, a port city on the country’s east coast and the location of a known submarine base.

In January, a research group at Johns Hopkins University ‘s U.S.- Korea Institute said on its website, 38 North, that satellite imagery showed possible evidence of work on vertical launch tubes on a submarine that could be for ballistic missiles.

The vessel could serve “as an experimental test bed for land-attack submarines”, 38 North said in a report, although it cautioned such a test would be expensive and time-consuming “with no guarantee of success”.

North Korea ‘s state media often boasts of successful military and space accomplishments, including the launch of a functional communications satellite, which do not get independently verified by outside experts.

But it is widely believed to have succeeded in launching a long-range rocket and putting an object into orbit in December 2012 defying widespread scepticism and international warnings not to pursue such a programme, which could be used to develop intercontinental missiles.

The North has an arsenal of land-based ballistic missiles and last test-fired a mid-range missile in March last year, drawing further condemnation from the international community.