The Korean won has come under renewed pressure, reversing much of its recent gains against the U.S. dollar as tighter U.S. monetary policy, higher oil prices and reduced dollar supply in the local foreign exchange market weigh on the currency, analysts said Tuesday. The won-dollar exchange rate rose nearly 50 won over seven consecutive trading sessions through Friday from its Sept. 9 level, bringing the 1,400-won mark back into focus. The exchange rate has fluctuated sharply in recent weeks. It stood at 1,411.8 won per dollar on Aug. 18 and slid to a 23-month low of 1,336.1 won on Sept. 9 as dollar selling by major semiconductor exporters increased foreign currency supply. That trend quickly reversed the following day, with the rate rising for seven straight sessions through Friday, up 47.2 won from its Sept. 9 close. The won recovered some ground Tuesday, with the rate retreating to close onshore trading at 1,358.2 won per dollar. The U.S. Federal Reserve’s rate hike has been a key factor behind the recent rise in the exchange rate. The Fed raised its benchmark rate by 25 basis points a