South Korea on Tuesday protested Japan's renewed territorial claim over a set of disputed islets lying equidistant between the two countries.

Japan's Cabinet approved its latest annual defense white paper earlier in the day, claiming the islets, known as Dokdo here and Takeshima in Japan, are an integral part of the Japanese territory.

It marked the eighth time Japan made such claims in the defense white paper.

South Korea "strongly protests" the latest territorial claims, the foreign ministry here said in response, demanding Japan " immediately withdraw" the "unacceptable" claims.

The islets belong to South Korea historically, geographically and under international law, the ministry said in a statement.

The defense ministry in Seoul issued a similar statement, vowing to "resolutely deal with any kind of attempt to" undermine South Korea's sovereignty.

"We urge the Japanese government to come to the realization that Japan cannot expect improvement in defense relations with South Korea unless it gives up on its territorial ambition," the ministry said.

The foreign and defense ministries summoned senior Japanese officials separately to officially protest the move.

The lonely set of outcroppings in the East Sea has been a chronic source of diplomatic row between the two Asian neighbors.

South Korea has maintained its control of the sparsely inhabited islets for decades since the end of Japan's 1910-45 colonial rule and is building a naval base on Ulleung Island, some 90 km west of the islets in question.

Many South Koreans see the recurring territorial disputes as a sign that Japan is not entirely repentant of its colonial past.

The former colonial master's latest claim came at a particularly sensitive time when the South Korean government is copping criticism for its attempt to seal a hush-hush military deal with Japan.

Recent public outcry over the secretive nature of the Cabinet endorsement of the intelligence-sharing agreement, called General Security of Military Information Agreement (GSOMIA), forced the government to scrap the plan to sign the accord earlier this month.

The two countries also remain at odds over compensation for Korean women who were forced into sexual slavery by the Japanese military during WWII, often euphemistically called "comfort women. "

"The Japanese government knows no remorse," South Korea's conservative ruling Saenuri Party said in a statement, calling its move "barbaric."

"(Japan) still seems incapable of escaping its old imperial ambitions," the ruling party said.