The military of the Democratic People's Republic of Korea (DPRK) warned on Saturday that it will "blow up" South Korea's loudspeakers and other propaganda tools.

The DPRK military "would blow up with sighting shots loudspeakers and all other means for a psychological warfare in case the group of traitors resumes the psychological warfare against the DPRK in the areas along the front," said a declaration issued by the General Staff of the Korean People's Army (KPA) via the KCNA official news agency.

It said the move was aimed at defeating South Korea's attempt to resume the psychological warfare against the DPRK.

From a military point of view, the installing of means for psychological warfare is "a direct declaration of a war against the DPRK," said the declaration.

"The KPA would launch an all-out military strike to blow up the group's means for the psychological warfare against the DPRK in all areas along the front," said the declaration.

It warned that the "decisive" military strike, which was not "a tit-for-tat retaliation," would turn South Korean capital Seoul into "a sea of flame."

Relations between South Korea and the DPRK have deteriorated since a South Korean navy corvette sank on March 26 near the maritime border between the two sides after an unexplained explosion.

Fourth-six sailors onboard the 1,200-ton Cheonan were killed in the incident.

South Korea said after completing investigation that the warship was torpedoed by the DPRK. But Pyongyang denied its involvement in the incident.

On June 4, South Korea formally referred the case of the warship sinking to the United Nations Security Council, urging it to discuss the issue and take firm measures to "punish the DPRK".