North Korea Says Spy Satellite Launch Ends In Failure, Again

North Korea's latest attempt to put a spy satellite into orbit has ended in failure, state media said Thursday, just months after Pyongyang's first launch crashed into the ocean shortly after blast off.

North Korean leader Kim Jong Un has made the development of an eye in the sky a top regime priority, with his nuclear-armed country claiming it is a necessary counterbalance to growing US military activity in the region.

North Korea's National Aerospace Development Administration "conducted the second launch of reconnaissance satellite Malligyong-1 aboard the new-type carrier rocket Chollima-1 at the Sohae Satellite Launching Ground in Cholsan County of North Phyongan Province at dawn of August 24," state media said.

"The flights of the first and second stages of the rocket were normal, but the launch failed due to an error in the emergency blasting system during the third-stage flight," the report in the official Korean Central News Agency added.

It claimed "the cause of the relevant accident is not a big issue" and vowed to conduct a third launch in October after probing the problem and taking measures to fix it.

South Korea's Joint Chiefs of Staff said it had detected the launch at around 3:50 am (1850 GMT Wednesday) of "what North Korea claims is a space launch vehicle," saying the projectile had "traversed the international airspace" over the Yellow Sea.

"Our military is maintaining a full readiness posture and closely coordinated with the United States, while simultaneously elevating our security posture," the JCS added.

The launch was first signalled by the Japanese government, which said Pyongyang had used banned ballistic missile technology and that the projectile had gone through the country's airspace near Okinawa.

"This latest launch by North Korea is extremely problematic from the perspective of ensuring the safety of affected residents as well as aircraft and ships," said Japan's top government spokesman Hirokazu Matsuno.

Pyongyang told Japan's coast guard on Tuesday that its launch would take place between August 24 and 31, prompting Tokyo to mobilise ships and its PAC-3 missile defence system in case anything was to land in its territory.

The launch came days after leaders from Washington, Seoul and Tokyo met at Camp David in the United States, and follows the launch of major US-South Korea joint military drills Monday.

Known as Ulchi Freedom Shield, the annual exercises, which always infuriate Pyongyang and have already been targeted by North Korean hackers, will run through August 31.

"Though still a failure, the flight progressed further than the previous attempt," Joseph Dempsey, a researcher at the International Institute for Strategic Studies, told AFP.

"Space is hard, with failure and lessons learnt often part of the development of ultimately successful evolving designs," he said, adding it was "unclear exactly what (North Korea) meant by emergency blasting system, possibly a reference to separation of the third stage."

In May, Pyongyang launched what it described as its first military reconnaissance satellite, but the rocket carrying it, the "Chollima-1" -- named after a mythical horse that often features in official propaganda -- plunged into the sea minutes after takeoff.

The crash sparked a complex, 36-day South Korean salvage operation involving a fleet of naval rescue ships, minesweepers and deep-sea divers.

The retrieved parts of the rocket and the satellite were analysed by experts in South Korea and the United States, who later said it had no military utility as a reconnaissance satellite.

North Korea's ruling party "bitterly" criticised the officials responsible for the crash in June, according to state media.

Relations between the two Koreas are at their lowest point in years, and diplomacy is stalled after failed attempts in recent years to discuss Pyongyang's denuclearisation.

Kim has declared North Korea an "irreversible" nuclear power and has called for ramped-up arms production, including tactical nuclear weapons.