North Korea made a false claim about the April 23 launch of its submarine-launched ballistic missile, multiple government sources in Seoul said Sunday, saying the missile is presumed to have exploded in the air.

"It is believed that the SLBM that the North launched on the 23rd from the East Sea flew about 30 kilometers before exploding," a government source said, noting that the missile may have split into two to three pieces without any booster separation.

The 30 km is far below SLBMs' minimum range of 300 kilometers, the source added.  

"One of the most convincing possibilities is that the North Korean military commanders and missile developers submitted fake reports to their leader Kim Jong-un, alleging the SLBM launch was successful," the source said. "The North's SLBMs have not reached the level where they can be deployed to deliver a nuclear bomb."

North Korea's media claimed on April 24 that it successfully launched an SLBM the previous day in the presence of leader Kim Jong-un that can greatly advance the fighting capability of its navy. It quoted Kim as saying that with the SLBM launch, the North now possesses a powerful nuclear weapons arsenal and a credible delivery system. 

SLBMs, if launched underwater, are very hard to counter because such a missile cannot be detected until it is airborne.  

In the past two months, North Korea has made four failed attempts to launch ballistic missiles. 

On March 18, North Korea launched two ballistic missiles named "Rodong," one of which exploded in the air before reaching its target. On April 15, the birthday of late North Korean ruler Kim Il-sung, the communist country fired an intermediate-range ballistic missile called a "Musudan" that ended up in a similar manner. 

On April 28, the North again launched two Musudan missiles, one in the morning and one in the afternoon, but both ended in failure.

The former missed the target and crashed on a beach, and the latter burst in midair. 

A South Korean government official said, "Outbound sales of missile technology have been one of Pyongyang's key sources for collecting foreign money, but the business may lose steam due to the North's repeated missile launch failures."  (Yonhap)