North Korea is reportedly making preparations for its fourth launch of a military spy satellite at its western satellite launching facility in Tongchang-ri.

According to Yonhap News Agency, citing a military source on Thursday, the North had previously installed screen fences before launching a satellite and similar fencing was recently set up at the Sohae Satellite Launching Station.

The source said authorities confirmed that the North conducted combustion tests for all three stages of propulsion systems to be loaded onto the satellite, but that it remains unclear whether the propellant has been moved to the launch site.

While the source said it is still difficult to forecast the exact timing of the launch, another source said no satellite would likely be fired in the next several days as the propulsion system is not believed to have been erected on the launch pad.

Last November, Pyongyang succeeded in putting the Malligyong-1 reconnaissance satellite into orbit after its third attempt, but the satellite is reportedly not functioning properly.