South Korea's largest oil spill reached part of the country's scenic and environmentally sensitive western shore Saturday as the Coast Guard struggled in high waves and strong winds to keep more oil from washing up on beaches.

Hundreds of troops, police and residents used buckets to remove dense crude oil from Mallipo — one of South Korea's best-known beaches — as tides of dark seawater crashed ashore. The odor could be smelled a kilometer (half a mile) away.

• Click here to view photos.

The region is popular for its scenic beaches and is also the site of fish farms, a national maritime park and is an important rest stop for migrating birds.

Mallipo, about 150 kilometers (95 miles) southwest of Seoul, is one of the hardest-hit areas from the oil spill, which occurred Friday when a crane-carrying barge slammed into a supertanker, punching holes and causing it to release 66,000 barrels of oil into the ocean.

The spill was the country's largest, involving twice as much oil as the worst previous spill in 1995.

The accident occurred about 7 miles (11 kilometers) off Mallipo.

The oil reached shore Saturday morning, contaminating about 7 kilometers (4 miles) of coastline near Mallipo, said Jung Se-hi, a spokesman at the Coast Guard headquarters in Incheon. Strong winds and prevailing currents spread the oil slick overnight to an area about 1 mile (2 kilometers) wide and 10 miles (20 kilometers) in length, he said.

Environmental activists expressed anguish over the situation.

"It's helpless," said Lee Pyong-gook, an activist with the Korean Federation for Environmental Movement. "It's a sea of oil."

Lee said the region is a major stopover for migratory snipe. "It was fortunate that those birds have yet to arrive," he said, adding however, that some seagulls had been tarred by oil.

The Coast Guard were mobilizing 103 vessels and six helicopters Saturday in an effort to clean up the spill, the Coast Guard's Jung said, adding that the operation was expected to take at least three days.

"We're doing our best to remove the contamination as quickly as possible, but it will take some time to clean up the shore because it needs to be done by hand," said Kim Woon-tae, a Coast Guard official stationed in the region.

Kim said oil was still trickling out of the punctured tanker, but the holes would soon be sealed completely. The Coast Guard headquarters had said Friday that all three holes in the tanker were plugged.

"It's a difficult operation because weather is not good," Kim said. "We're focusing our efforts on preventing more oil from reaching the coast."

The size of the leak reported by the authorities would be about one-fourth that of the 260,000 barrels, or 11 million gallons, of oil spilled into Alaska's Prince William Sound by the Exxon Valdez in 1989.

The tanker, the Hebei Spirit, and the other vessel, owned by South Korea's Samsung Corp., were in no danger of sinking, the Coast Guard said. There were no casualties in the accident.

The tanker was at anchor and carrying about 260,000 tons of crude oil — about 1.8 million barrels — to be loaded into boats from a nearby port when it was hit by the South Korean barge which was being towed by a small tug boat, said Kim Tae-ho, another Coast Guard official.

The barge, which was moving from a construction site, lost control after a wire linking it to the tug boat was cut due to high winds, waves and currents, he said.

Kim said the Coast Guard planned to question the barge's captain to find why he was sailing through the area despite the stormy weather.

The July 1995 leak caused damage estimated at 73.5 billion won, at today's exchange rates equal to US$80 million.