North Korea on Sunday accused Japan of "illegally intruding" into waters over which it exercises maritime rights and warned of possible "strong countermeasures."

The Foreign Ministry, in a post on its website, said the problem affecting North Korea's "economic waters" in the Sea of Japan, which it called the "East Sea" by its Korean name, "has become a reality in recent years."

It said the issue was discussed Saturday at a conference joined by the Standing Committee of the Supreme People's Assembly, the General Staff of the Korean People's Army, the Foreign Ministry and the Ministry of Land and Environment Protection.

Although the post did not mention specific cases of Japanese intrusion in contested waters, it was apparently alluding to the movements of Japanese fishing and coast guard vessels in areas where the exclusive economic zones claimed by each country overlap.

On Oct. 7, 2019, for example, dozens of North Korean fishermen were rescued Monday when their boat sank after colliding with a Japanese patrol vessel that had warned it to get out of Japan's EEZ.

The incident took place some 350 kilometers northwest of the Noto Peninsula in Ishikawa Prefecture, near an area called Yamatotai that is known as fertile waters for squid and fish.

Then Prime Minister Shinzo Abe subsequently vowed in parliament that Japan would "take resolute action to prevent illegal operations by foreign ships within Japan's EEZ."

The two countries also dispute ownership of the Japanese-claimed, South Korean-controlled island of Dokdo, known in North Korea as Tok Island.