The Democratic People's Republic of Korea (DPRK) on Friday warned Seoul of "strikes without any prior warning" targeting South Korean naval ships if they continue to intrude into waters of the DPRK.

The command of the Korean People's Army (KPA) in the southwestern front issued a special warning, carried by the official news agency KCNA, accusing South Korea of sending 17 naval boats over the past seven days into the DPRK's territorial waters.

Also, the warning said, five speedboats of the South Korean navy had intruded several times into the DPRK waters on April 26.

Pyongyang said Seoul's real purpose was to defend the Northern Limit Line, or NLL, a maritime demarcation line between the two Koreas which Pyongyang has denied and called "illegal."

"Such reckless intrusions are escalating in the hotspot waters in the overall southwest sea," the warning said.

It added that the DPRK military will launch more retaliatory attacks should "provocateurs challenge the self-defensive strikes."

"There is a limit to the patience of the KPA service personnel, " the warning said, suggesting that the DPRK military never makes empty talk.