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.