Police arrested a South Korean women on suspicion of burning down several buildings at a U.S. Army base in Seoul on Thursday because she was angry at what she saw as "U.S. terrorism." Three South Korean civilian employees were injured in the fire that started at a public works building at the base that serves as the headquarters for U.S. troops in South Korea. The fire spread to four other buildings, police said.Police said they apprehended a 57-year-old woman who they suspect sneaked into the base and set fire to one building with a cigarette lighter. "She at one point said it was punishment for U.S. terrorism," a police officer said by telephone. Police said the woman apparently had a history of mental illness. There are about 30,000 U.S. troops in South Korea to support some 690,00 South Korean troops in defense of the peninsula. Protests against the U.S. military presence in South Korea are a regular occurrence in the country.