SEOUL - South Korea's presidential office said on Wednesday the issue of US troops stationed in the South is unrelated to any future peace treaty with North Korea and is a matter regarding Seoul's alliance with Washington. Kim Eui-kyeom, a spokesman for the presidential Blue House, was responding to media questions about a column written by South Korean presidential adviser and academic Moon Chung-in that was published earlier this week. Presidential adviser Moon said it would be difficult to justify the presence of US forces in South Korea if a peace treaty was signed.