N. Korea Test-Fires Submarine-launched Ballistic Missile

North Korea on Saturday test-fired a submarine-launched ballistic missile (SLBM), Seoul's defence ministry said, a day after the US and South Korea decided to deploy an advanced missile defence system in the South.

The launch was apparently successful but the missile failed in the early stage of flight, the South Korean defence ministry said in a statement.

Yonhap news agency said the missile, launched from a Sinpo-class submarine, reached an altitude of around 10 kilometres (six miles) before exploding in mid-air. North Korea previously successfully fired an SLBM on April 23.

Seoul said the North launched "what was believed to be an SLBM" from waters off the northeastern port of Sinpo at around 11:30 am (0230 GMT).

The US Strategic Command said the missile was tracked over the Sea of Japan, where initial indications suggested it fell, AFP reported.

Seoul's defence ministry noted that "North Korea has been persistent in violating UN resolutions by launching ballistic missiles continuously".

It added that the North carried out back-to-back tests of a powerful new medium-range missile on June 22, which sparked swift international condemnation.

The two missiles achieved a significant increase in flight distance over previous failed launches and were believed to be of a much-hyped, intermediate-range Musudan missile -- theoretically capable of reaching US bases as far away as Guam, the ministry said in June.