N. Korea fires submarine-launched missile: S. Korea

South Korea military says North Korea has fired a submarine-launched ballistic missile off its east coast, flying it for about 30 miles or 18 kilometers.

It comes amid concern that North Korean leader, Kim Jong Un -- seen here in 2015, might order a nuclear missile test ahead of a rare ruling party meeting in May.

That's when he's expected to say the isolated country is a strong military power and a nuclear state.

Under U.N. sanctions, North Korea is banned from nuclear tests and activities that use ballistic missile technology.

But Pyongyang has pushed ahead anyway to develop a miniature nuclear warhead as well as an intercontinental ballistic missile.

Pyongyang first tried to launch a submarine-based missile last year and was thought to be in the early stages of developing that kind of a weapons system.

But it's thought its follow up tests to the launch didn't go well and the South Korean military is now trying to find out if Saturday's launch may have been a failure.

Still, if perfected, a submarine-based missile could pose a new threat to North Korea's neighbors as well as the United States.