"Japan's claim does not deserve any consideration," the ministry said in a release. "As Dokdo is our inherent territory historically, geographically and by international law, we make it clear that we will sternly respond to any outside intrusion into Dokdo."

During the Russian plane's airspace intrusion, the Japanese Self-Defense Air Force also scrambled its fighter jets, according to Suga.

Japan's renewed territorial claim came at a time when the Seoul-Tokyo ties have plunged to their lowest ebb over Japan's recent export restrictions on South Korea. It is seen as political retaliation for last year's Supreme Court rulings here against Japanese firms over wartime forced labor.

South Korea maintains a small police unit on the pair of rocky outcroppings to show its effective control over the land. Japan has repeatedly laid claim to the islets.

Seoul's defense ministry had planned to express strong regrets to Russia over the airspace intrusion, but it dropped the plan after the presidential office Cheong Wa Dae earlier said that Russia had expressed "deep regret" over the incident, saying that a technical problem appears to have caused the plane to have trespassed in the airspace.

Apart from the reconnaissance plane, two Russian bombers and two Chinese warplanes also entered South Korea's air defense identification zone near the islets without prior notice Tuesday.

The two sides said they had conducted the first combined air patrol.

A Seoul ministry official, however, said that South Korea does not believe such an incident could be caused by a technical glitch.

"Upon launching a probe into the incident, Russia today asked us for data related to the airspace intrusion," the official said, adding that the ministry is reviewing the scope of the information it could provide to Moscow.

The ministry is also preparing for working-level meetings with Russia over the issue, according to the official.

But it is unclear as of now what stance Russia officially has taken regarding the airspace violation.

According to Russia's TASS news agency, Russia's defense ministry denied any violations, saying their jets had carried out planned drills over international waters.

Sergei Kobylash, the commander of the Russian aerospace forces, even called the actions taken by South Korea "aerial hooliganism," the news agency reported. (Yonhap)