SEOUL, Dec 17 (Reuters) - South Korea’s central bank on Thursday said it has agreed to renew an existing currency swap agreement with the U.S. Federal Reserve by another six months to at least Sept. 30, 2021. Both sides agreed that the extension of the $60 billion currency swap deal is needed in a preemptive measure to counter the uncertainties caused by a resurgence in coronavirus globally, despite a recovery in risk appetite and stabilised local currency market. The Bank of Korea had suspended dollar auctions after injecting a total $19.872 billion through six separate auctions. (Reporting by Joori Roh; Editing by Stephen Coates)