Pyongyang, North Korea - North Korea on Tuesday slammed US President Donald Trump's "Golden Dome" missile shield plan as a "very dangerous" threat that could spark nuclear war in space.

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.

In a statement shared by the Korean Central News Agency (KCNA), Pyongyang's foreign ministry slammed the "very dangerous 'threatening initiative' aimed at threatening the strategic security of the nuclear weapons states".

The US is "hell-bent on the moves to militarize outer space," the foreign ministry said.

"The US 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... outer space into a potential nuclear war field."

Washington -- Seoul's key security ally -- has in recent years ramped up joint military exercises and increased the presence of strategic US assets, such as an aircraft carrier and a nuclear-powered submarine, in the region to deter the North.

Pyongyang has repeatedly declared itself an "irreversible" nuclear weapons state and routinely denounces joint US-South Korea drills as rehearsals for invasion.

China has also expressed strong concerns about Washington's Golden Dome plan, accusing the US of undermining global stability.

Russia, meanwhile, said Trump's initiative would require consultations but was otherwise a "sovereign matter" for the US.

The White House put the cost of the project at $175 billion, but the Congressional Research Office's calculations indicated the true number would pass half a trillion dollars.