A South Korean destroyer locked its fire-control radar onto a Japanese patrol plane last week “multiple times,” the Defense Ministry said Tuesday, in its latest rebuttal of Seoul’s insistence that the lock-on was not intentional.

“We have confirmed that it continued for a certain period of time and … multiple times,” the ministry said in a statement.

The ministry said the new assertion is based on its analysis of the frequency and intensity of radio waves emitted by the destroyer at that time in the Sea of Japan.

“It is extremely regrettable that this kind of incident occurred and we will strongly urge South Korea to prevent a recurrence,” the ministry said, adding that Japan is prepared to hold talks with South Korea as defense cooperation between them should not be damaged.

The statement was released a day after Japanese and South Korean diplomats clashed over the issue at a director-general level meeting held in Seoul. Tokyo has claimed that the destroyer directed its fire-control radar at the Maritime Self-Defense Force P-1 patrol plane at around 3 p.m. on Thursday, calling it an “extremely dangerous act” and a step away from actual firing.

“South Korea has expressed its views, but there are some factual mistakes,” Defense Minister Takeshi Iwaya said at a news conference Tuesday.

Japan asserts that its MSDF aircraft made inquiries to the destroyer in English three times using three different frequency bands, but the South Korean counterpart gave no answer when asked about the locking of the radar.

In response to South Korea’s claim that the Japanese aircraft was flying toward the warship, the ministry said, “It’s not the case that the P-1 flew low over the destroyer,” adding that the plane maintained adequate altitude and distance from the vessel and that its flight was in line with international and domestic laws.

South Korea has denied that the radar was used to track the plane on purpose, and said no dangerous actions were performed.

A South Korean military official said the destroyer was at the scene at the time to rescue a North Korean boat in distress and was using an optical camera.

Japanese government sources said over the weekend that the South Korean destroyer targeted its radar intentionally at the aircraft for a “few minutes.”

The ruling Liberal Democratic Party held an urgent meeting on national defense and security in the morning, during which some lawmakers requested that senior Japanese officials demand an apology from South Korea.