SEOUL (AFP) - An elderly South Korean man died from his injuries on Friday, nine days after setting himself on fire to protest Japan's forced recruitment of sex slaves for military brothels during World War II.

Doctors treating Mr Choi Hyun Yul, 81, said his condition had deteriorated rapidly due to blood poisoning.

Mr Choi set himself alight during a rally by some 1,000 protesters outside the Japanese embassy in Seoul on Aug 12, ahead of the 70th anniversary of the end of Japan's 1910-45 colonial rule over the Korean peninsula.

Mr Choi had been a regular at the monthly protests outside the embassy to demand reparations for so-called "comfort women" - an extremely emotive issue in South Korea where fewer than 50 of the thousands of women coerced into prostitution remain alive.

Japan says the issue was settled in the 1965 bilateral agreement that restored diplomatic ties between the two nations, which saw Tokyo make a total payment of $800 million in grants or loans to its former colony.

Self-immolation is not that rare a form of protest in South Korea, and was particularly common during the pro-democracy movement of the 1980s and early-90s, when a number of student activists set themselves on fire during public demonstrations.

The last such protest outside the Japanese embassy was in 2005, when a 54-year-old man set himself on fire during a protest over Japan's claim to a set of South Korean-controlled islets in the East Sea (Sea of Japan).