North Korea fired missiles on Wednesday (Sept. 15) as part of a test of a new "railway-borne missile system" planned as a potential counter-strike against any forces threatening the country.

According to state news agency KCNA, the missiles flew 800 kilometers (497 miles) before striking a target in the sea off North Korea's east coast.

Photos released by state media showed an olive-green missile rising from the roof of a train halted on tracks in hilly terrain on a plume of smoke and flame.

The missiles were launched from Yangdok's center inland area, according to South Korea.

The North Korean launches coincided with South Korea's successful test of a submarine-launched ballistic missile (SLBM), making it the first country without nuclear weapons to do so.

Both Koreas have been engaged in an increasingly heated arms race, with each side announcing new, more capable missiles and other weaponry.

South Korean and Japanese authorities said on Wednesday that they had detected the launch of two ballistic missiles by North Korea, only days after it launched a cruise missile with nuclear capabilities, according to analysts.

North Korea's nuclear tests sparked global condemnation and alarm, with the U.S. claiming that they breached UN Security Council resolutions and represented a threat to Pyongyang's neighbors.

Members of the Security Council gathered behind closed doors for an emergency meeting to discuss North Korea's latest ballistic missile launch, which member states regard as a "major threat," according to Nicolas de Riviere, France's UN ambassador.

"Everyone is very concerned about this situation," de Riviere told several journalists after the 45-minute meeting.

"This is a major threat to peace and security, it's a clear violation of the Council's resolutions," he added, saying that the missiles had fallen "within Japan's exclusive economic zone."

The string of launches is seen to be part of a strategy to give the regime advantage in future talks with the US or South Korea.

North Korea's missile launch on Wednesday marked the country's fifth provocation this year.

Analysts believe that the railway system demonstrated on Wednesday might pave the way for the development of a larger, nuclear-armed intercontinental ballistic missile (ICBM).