South Korea's external debt rose to a record high in the first quarter mainly due to overseas investors buying local bonds and banks' foreign borrowing, the Korean central bank said Tuesday. The country's external debt totaled US$411.4 billion as of the end of March, up $13 billion from the previous quarter, according to a report by the Bank of Korea (BOK). The country held $275.1 billion in long-term foreign debt, with short term debt totaling 136.3 billion, South Korea's news agency (Yonhap) reported. The size of South Korea's debt is not a source of concern, however, the bank added, because of the country's overall size and its trade-oriented economic structure. The increase was caused mostly by long-term debt that rose by $12.8 billion in the cited period, while short-term debt due to mature in less than a year edged up by just $200 million, the report said. "Foreign investors purchasing $10.8 billion in domestic bonds played a part in the increase, while measures taken by South Korean lenders to stockpile foreign liquidity in the face of persistent eurozone woes also contributed to the increase," the central bank said. Many short term debts were converted into long term arrangements that reduced the lenders' exposure to sudden developments, the BOK said. Reflecting this, short-term debt made up 33.1 percent of all debt, down from 34.2 percent for the fourth quarter of 2011. Short-term debt also equaled 43.1 percent of the money the country has set aside to handle payments, which is a decrease from 44.4 percent tallied at the end of last year. The BOK said total debt accounted for 35.7 percent of the country's gross domestic product as of last year, much less than the numbers for European countries, the United States and Japan. By keeping close track of external developments taking place in Greece and other eurozone members, Seoul plans to respond "flexibly" to any sudden changes, it said. The latest report showed South Korea's external credit reached $510.9 billion as of the end of March with the country holding net credit of $99.5 billion, up $1.5 billion from three months earlier. Foreign investment in South Korea rose to $896.0 billion in the first quarter as overseas investors bought more stocks and bonds. This is a gain of $56.8 billion from late last year. Outbound foreign investment, including securities investment, stood at $769.2 billion as of the end of March, up $27.2 billion from the previous quarter, the BOK said. The Korean finance ministry said a rise in debt caused by foreign investors buying local bonds reflects the country's solid economic fundamentals and expectations on future growth.