North Korea said Tuesday a patrol boat and ships of the Japan Coast Guard "made illegal intrusion" into its exclusive economic zone late last month.

The North's official Korean Central News Agency quoted a Foreign Ministry spokesperson as saying that the vessels were chased out by the country's "self-defensive measures."

The report came after Japanese officials last week revealed an incident in which a crew member with a rifle aboard a high-speed vessel, likely from North Korea, threatened to fire at a patrol boat in the Sea of Japan in late August.

The officials said three crew members wearing camouflage clothing were aboard the high-speed vessel, with one pointing a rifle at the patrol boat and another filming the encounter on Aug. 24, adding that the incident occurred near an area in the sea called Yamatotai — within Japan's EEZ.

Yamatotai is known for its rich fishing grounds. Tokyo has lodged a strong protest with North Korea through the Japanese Embassy in Beijing, Chief Cabinet Secretary Yoshihide Suga said Friday.

The KCNA report Tuesday said the "expulsion of the Japanese ships from our zone is a just and righteous exercise of our sovereign rights."