Pyongyang's foreign ministry has issued a memorandum calling the system "a very dangerous 'threatening initiative' aimed at threatening the strategic security of the nuclear weapons states," the Korean Central News Agency (KCNA) said.

Trump announced new details and initial funding for the missile shield system last week, calling it "very important for the success and even survival of our country."

The initiative faces significant technical and political challenges, according to analysts, and could come at a hefty price tag.

The memorandum by nuclear-armed North Korea accused the United States of being "hell-bent on the moves to militarize outer space," KCNA said.

"The U.S. plan for building a new missile defense system is the root cause of sparking off global nuclear and space arms race by stimulating the security concerns of nuclear weapons states and turning the outer space into a potential nuclear war field," it added.

China has similarly expressed strong opposition to the plan, accusing the United States of undermining global stability.