The Democratic People's Republic of Korea (DPRK) declared a plan on Thursday to liquidate all of South Korean assets in the DPRK, while nullifying all inter-Korean economic cooperation projects in response to Seoul's unilateral sanctions against Pyongyang.

The DPRK's Committee for the Peaceful Reunification of Korea (CPRK) said in an unnamed spokesman's statement that its country declares all of inter-Korean agreements, which are relevant to economic cooperation and exchange projects, "null and void" from now on.

The statement said the decision was made in response to a series of unilateral sanctions unveiled Tuesday by Seoul on the DPRK after the UN Security Council voted to adopt a tough resolution against Pyongyang earlier this month.

DPRK started off a new year with the testing of what it claimed was its first hydrogen bomb on Jan. 6 and followed up with the launch of a long-range rocket, which outsiders see as a disguised test of missile technology, on Feb. 7.

The UN Security Council unanimously approved new tougher sanctions on Pyongyang on March 2, including a ban on all cargo heading to and from the DPRK and its exports of coal and mineral resources.

South Korea imposed standalone sanctions on the DPRK, including a ban on third-country ships having docked at the DPRK within 180 days from accessing South Korean ports.

The standalone sanctions came after Seoul announced a plan to shut down the inter-Korean factory park in the DPRK's border city of Kaesong on Feb. 10, three days after Pyongyang's satellite launch.

The CPRK statement said that special measures will continue to be taken to bring forward a "miserable demise" of the South Korean government by inflicting political, military, and economic damages. It didn't elaborate on which measures would be taken further.

The statement noted that DPRK forces turned to a "pre-emptive" strikes strategy, which can put enemies in a sea of fire at a blow, threatening that South Korea's presidential office Cheong Wa Dae lies within a range of its first strike by DPRK forces.

The military threat was Pyongyang's repeated response to the largest-ever joint annual war games between Seoul and Washington that kicked off on Monday.

The drills, codenamed Key Resolve and Foal Eagle, will run by the end of April, mobilizing a U.S. nuclear-powered aircraft carrier and its attendant fleet, a nuclear-capable submarine and aerial tankers to refuel fighter jets.

Calling the war games as "undisguised nuclear war drills," the DPRK warned of "pre-emptive and aggressive nuclear strikes" against South Korea and the U.S. mainland, saying it had a military operation plan for such nuclear strikes.

Top DPRK leader Kim Jong Un has ordered his country's nuclear warheads for national defense to be placed always on standby for use at any time.