Korea's presidential office denied a news report Friday that Japanese Prime Minister Yoshihiko Noda mentioned the issue of Korean women sexually enslaved by Japan during World War II in a letter sent to President Lee Myung-bak.

Japan's Kyodo News reported Noda's letter, delivered to Seoul by Deputy Chief Cabinet Secretary Tsuyoshi Saito, touched on the sexual slavery issue among others. Saito was quoted as saying the letter was aimed at paving the way for next month's three-way summit between South Korea, Japan and China.

A senior official at South Korea's presidential office said the office received the letter from Saito but it made no mention of the historic sexual slavery. The letter would be relayed to President Lee soon, the official said.

"There is nothing related to comfort women," the official said on condition of anonymity, using the euphemistic term for the former sex slaves. "A letter between leaders is not supposed to be made public. There is nothing (in the letter) that the press might be interested in."

Presidential spokesman Park Jeong-ha said he understands the letter was about cooperation between the two countries, including South Korea's hosting of the Nuclear Security Summit last month and North Korea's rocket launch.

The sexual slavery issue has long been a thorn in relations between Seoul and Tokyo.

South Korea wants Japan to take steps to address long-running grievances of elderly Korean women who suffered as sex slaves. Lee has strongly urged Japan to resolve the issue, stressing it is becoming increasingly urgent as most victims are well over 80 years old and may die before they receive compensation or an apology from Japan.

Tokyo has ignored Seoul's demand, maintaining that all issues regarding its colonial rule of the Korean Peninsula, including the comfort women issue, were settled in a 1965 package compensation deal under which the two countries normalized their relations. (Yonhap)