North Korea has set up three new antiaircraft artillery bases in the outskirts of Pyongyang as part of its efforts to defend the North Korean capital and its military facilities, the U.S.-based Radio Free Asia said Thursday.

Citing Curtis Melvin, a researcher at the U.S.-Korea Institute at Johns Hopkins University, the RFA said a satellite imagery analysis of the antiaircraft artillery bases suggests they are situated in eastern Pyongyang and an existing antiaircraft artillery base is reinforced with an underground facility.

The expansion of the North's antiaircraft artillery force goes to show that the Kim Jong-un regime will not neglect its efforts to develop conventional weapons as well as nuclear arms and missiles, Melvin was quoted as saying.