The Democratic People's Republic of Korea (DPRK) warned Tuesday that it would "mercilessly avenge" any breach of its territorial sovereignty by South Korea or the United States during their ongoing anti-submarine drills in the Yellow Sea.

The Southwestern Front Command of the Korean People's Army said all units and sub-units of the military in the region will simultaneously start military actions in accordance with operation plans ratified by the supreme command, the official news agency KCNA said.

It warned that if South Korea or the U.S. responds "recklessly" to DPRK's counteractions, prompt actions by rocket forces deployed in the southwestern sector will turn the five islands in the Yellow Sea into a "sea of flames."

South Korea and the United States launched a five-day joint naval military drill on Monday in the Yellow Sea with the participation of a nuclear-powered Los Angeles-class submarine.

The anti-submarine regular exercises, which came in the wake of the two-month-long joint Foal Eagle military exercise, also involves Aegis destroyers and P-3C maritime surveillance aircraft deployed from U.S. bases.

Related to the latest warning, the DPRK said Sunday that if Seoul really worries about the future of the Kaesong industrial zone, it should stop all its hostile policy and provocative military drills toward Pyongyang.

However, South Korean defense ministry spokesman brushed off the warnings, saying that "as long as the combined forces and South Korean military exist, the drills will continue."