One of the most-powerful earthquakes in years triggered massive tidal waves that slammed into coastlines across Asia Sunday, killing more than 700 people in Sri Lanka, Indonesia, India, Malaysia and Thailand. Tourists, fishermen, homes and cars were swept away by walls of water unleashed by the 8.9-magnitude earthquake, centered off the west coast of the Indonesian island of Sumatra, where at least 94 people were killed by floods and collapsing buildings, officials said. But the scope of the disaster became apparent only after waves as high as six meters (20 feet) crashed into coastal villages over a wide area of Sri Lanka _ some 1,600 kilometers (1,000 miles) west of the epicenter _ and killed around 300 people. Elsewhere, 286 people were confirmed dead in India, 61 in Thailand and seven in Malaysia. Thousands of people were missing, many of them fishermen at sea, and rescue workers struggled against floodwaters to find and evacuate stranded victims. The death toll climbed throughout the day and was expected to grow even higher as more bodies were discovered. At least 100 bodies were found on various beaches in Madras, the capital of the southern Indian state of Tamil Nadu, and more were expected to be washed in by the sea, officials said. The U.S. Geological Survey's Web site recorded the magnitude 8.9 earthquake off the west coast of northern Sumatra, 1,620 kilometers (1,000 miles) northwest of Jakarta. It was centered 40 kilometers (25 miles) below the seabed. Aftershocks struck in the magnitude 7 range.