From The International Herald Tribune (link):
The Chinese ambassador to South Korea warned Wednesday that a new defense agreement between Washington and Seoul should never be used to allow U.S. troops based in South Korea to intervene in a possible conflict between China and Taiwan.
Ning Fukui was the first Chinese official to publicly raise concern about a recent U.S.-South Korean agreement on “strategic flexibility” that gave U.S. troops based in South Korea greater freedom to be deployed outside the Korean Peninsula.



