SEOUL - South Korea on Friday protested Japanese foreign minister's claim that South Korea is illegally occupying a set of disputed islets, the latest development in the diplomatic row between the two countries.

The foreign ministry here summoned a Japanese envoy and delivered a letter protesting Koichiro Gemba's recent description of South Korea's control over the islets as an "illegal occupation", according to local media reports.

The move came after South Korea sent back a letter Japanese Prime Minister Yoshihiko Noda wrote to his counterpart Lee Myung- bak, in which the Japanese leader protested Lee's high-profile visit to the disputed islets earlier this month.

In the letter, Noda also proposed taking the territorial dispute to the International Court of Justice, a move dismissed repeatedly by Seoul officials as "unworthy of consideration".

The proposed third-party arbitration is Japan's third attempt to bring international attention to the dispute over the islands known as Dokdo here and Takeshima in Japan, though the Hague-based court will not hear the case unless the two contending parties agree to the referral.

Lying equidistant between South Korea and Japan, the lonely set of islets coveted for rich mineral resources in the surrounding waters has been a chronic source of diplomatic tension between the two Asian neighbors.

South Korea has maintained its control over the rocky outcroppings since it regained independence from Japan's 1910-45 colonial occupation of the Korean peninsula.

With the two countries still at odds over a number of historical issues, many South Koreans see recurring territorial disputes as a sign of an unrepentant Japan.

Last month, South Korea's attempt to forge its first military pact with Japan since the end of the colonial rule was thwarted at the last minute by the outraged public weary of Japan's resurgent military ambitions.