A powerful earthquake flattened hundreds of buildings in western Indonesia on Tuesday, killing at least 70 people and leaving hospitals grappling with scores of injured, officials said. The number of dead was expected to rise as a result of the magnitude 6.3 quake on Sumatra island, which was followed by powerful aftershocks and was felt hundreds of kilometers away in Singapore, where some office buildings were evacuated, and in neighboring Malaysia. "Women were crying out in terror. We all just fled as quickly as we could," said Alpion, a welder in the seaside town of Padang. Along with thousands of others, he was fleeing to higher ground, fearing a possible tsunami. Authorities said the quake did not cause any tidal activity. Indonesian Cabinet Secretary Sudi Silalahi told reporters at least 70 people had been killed by the quake, the latest in a series of natural disasters to strike Indonesia in recent months. The worst-hit area appeared to be in and around Solok, a bustling town close to the epicenter of the quake on Sumatra's western coast, which was spared destruction in the 2004 Asian tsunami disaster. Two children and a teacher were killed in the town when a two-story building crashed onto a playground, said police spokesman Supriadi, who goes by only one name. Three family members were burned alive when their collapsed home burst into flames, town Mayor Samsu Rahim told a local radio station. Hospitals in Solok were overflowing with patients, many of them with broken bones and cuts, Supriadi said. At least one hospital in nearby Padang, which was spared serious damage, was evacuated, sending panicked doctors and nurses fleeing with startled patients limping behind, according to Metro TV. A witness in the town of Payahkumbuh said several two-story shops in the main street had collapsed and police and soldiers were digging for survivors. Local government spokesman Hasrul Piliang said the number of dead "would likely rise" because tolls from remote areas were still being collected and there were reports of others trapped under debris. The U.S. Geological Survey said the tremor struck 33 kilometers below Solok. It was followed by several strong aftershocks. The tremor and at least one of the aftershocks was felt in Singapore, 430 kilometers from the epicenter, forcing the evacuation of several older office buildings, TV station Channel NewsAsia reported. In Malaysia's southern coastal city of Johor, citizens fled offices, buildings and shopping centers, eyewitnesses said. Indonesia, the world's largest archipelago, is prone to seismic upheaval because of its location on the so-called Pacific "Ring of Fire," an arc of volcanos and fault lines encircling the Pacific Basin. In December 2004, a massive earthquake struck off Indonesia's Sumatra island and triggered a tsunami that killed more than 230,000 people, including 131,000 people in Indonesia's Aceh province alone. A tsunami off Java island last year killed nearly 5,000. Tuesday's quake hit about 900 kilometers west of the country's capital Jakarta.