Oil from a damaged supertanker has reached an ecologically sensitive shoreline on South Korea's western coast, a Coast Guard official said Saturday. About four miles (6.5 kilometers) of coastline near Mallipo beach, approximately 95 miles (153 kilometers) southwest of Seoul, has been affected, said Jung Se-hi, a spokesman at the Coast Guard headquarters in Incheon. The region is popular for its scenic beaches and is also the site of fish farms, a national maritime park and an important rest stop for migrating birds, the Associated Press reported. Some 2.7 million gallons of oil gushed Friday from a 146,000-ton Hong Kong-registered supertanker after a barge carrying a crane slammed into it about seven miles off Mallipo beach. The spill was the country's largest, involving twice as much oil as a spill in 1995. South Korea's Coast Guard dispatched dozens of ships Friday to try to contain the spill and keep it from reaching the sensitive shoreline. But strong winds and prevailing currents spread the oil slick to an area about 1 mile wide and 10 miles long, Jung said. The Coast Guard plans to mobilize 103 vessels and six helicopters Saturday in an effort to clean it up, Jung said, adding that the operation was expected to take at least three days.