North Korea's General Staff has threatened to launch an "all-out military counterattack" to destroy South Korean loudspeakers that Seoul has installed along the border to air propaganda broadcasts.

The North’s General Staff, which is the equivalent of South Korea’s Joint Chiefs of Staff, said in what it called a “crucial declaration” Saturday that the South’s move to resume psychological warfare violates the June 15th Joint Declaration and other inter-Korean military agreements that are based on the joint declaration.

The statement also called Seoul’s move to install the loudspeakers a major provocation infringing upon the North’s dignity and national interest. The statement noted that the South installed propaganda loudspeakers in eleven places along the border in response to the sinking of the Cheonan naval ship.

The statement said the South’s installation of loudspeakers is a declaration of war against the North as psychological warfare is a basic form of war. The North warned that by military counterattacks it means ruthless strikes that could turn Seoul into a "sea of fire."