A massive tsunami hurled by a powerful earthquake flattened Samoan villages and swept cars and people out to sea, killing at least 99 and leaving dozens missing Wednesday. The toll was expected to rise. Survivors fled the fast-churning water for higher ground on the South Pacific islands and remained huddled there hours after the quake, with a magnitude between 8.0 and 8.3, struck around dawn Tuesday. The quake was centered about 125 miles (200 kilometers) from Samoa, an island nation of 180,000 people located about halfway between New Zealand and Hawaii. It was about 120 miles (190 kilometers) from neighboring American Samoa, a US territory that is home to 65,000 people. Four tsunami waves 15 to 20 feet (4 to 6 meters) high roared ashore on American Samoa, reaching up to a mile (1.5 kilometers) inland, Mike Reynolds, superintendent of the National Park of American Samoa, was quoted as saying by a parks service spokeswoman. The UN Office for the Coordination of Humanitarian Affairs was dispatching an emergency team to area and the UN system was mobilizing to provide aid, a statement said. The Samoan capital, Apia, was virtually deserted by afternoon, with schools and businesses closed. Hours after the waves struck, fresh sirens rang out with another tsunami alert and panicked residents headed for higher ground again, although there was no indication of a new quake. In American Samoa's capital of Pago Pago, the streets and fields were filled with ocean debris, mud, overturned cars and several boats as a massive cleanup effort continued into the night. Several buildings in the city – just a few feet above sea level – were flattened. Several areas were expected to be without electricity for up to a month. In Washington, President Obama has declared a major disaster for American Samoa. In a statement issued early Wednesday, Obama said he and his wife, Michelle, “will keep those who have lost so much in our thoughts and prayers.” Hampered by power and communications outages, officials in the South Pacific islands struggled to determine damage and casualties. Samoan police commissioner Lilo Maiava said police had confirmed 63 deaths but that officials were still searching the devastated areas, so the number of deaths might rise soon. At least 30 people were killed on American Samoa, Gov. Togiola Tulafono said, adding that the toll was expected to rise as emergency crews were recovering bodies overnight. “I don't think anybody is going to be spared in this disaster,” said Tulafono, who was in Hawaii for a conference. He added that a member of his extended family was among the dead in the disaster. Authorities in Tonga confirmed at least six additional people dead in the island nation west of the Samoas, New Zealand's acting Prime Minister Bill English said. He said Tongan officials told him that four people were missing after the tsunami swept ashore on the northern island of Niua. Australian Prime Minister Kevin Rudd told Seven Network in Australia that two Australians had died, including a 6-year-old girl. The British Foreign Office said one Briton was missing and presumed dead. Samoan Prime Minister Tuilaepa Sailele Malielegaoi looked shaken Wednesday on board a flight from Auckland, New Zealand, to the Samoan capital of Apia. “So much has gone. So many people are gone,” he told reporters on board. “I'm so shocked, so saddened by all the loss.” Malielegaoi said his own village of Lepa was destroyed. “Thankfully, the alarm sounded on the radio and gave people time to climb to higher ground,” he said. “But not everyone escaped.” A New Zealand P3 Orion maritime surveillance airplane had reached the region Wednesday afternoon and had searched for survivors off the coast. The Samoa Red Cross estimated that about 15,000 people were affected by the tsunami. New Zealander Graeme Ansell said the Samoan beach village of Sau Sau Beach Fale was leveled. “It was very quick. The whole village has been wiped out,” Ansell told New Zealand's National Radio from a hill near Samoa's capital, Apia. “There's not a building standing. We've all clambered up hills, and one of our party has a broken leg. There will be people in a great lot of need ‘round here.” Residents in both Samoa and American Samoa reported being shaken awake by the quake early Tuesday, which lasted two to three minutes and was centered about 20 miles (30 kilometers) below the ocean floor. It was followed by at least three large aftershocks of at least 5.6 magnitude. The quake came Tuesday morning for the Samoas, which lie just east of the international dateline. For Asia-Pacific countries on the other side of the line, it was already Wednesday. While the earthquake and tsunami were big, they were not on the same scale of the 2004 Indian Ocean tsunami. That tsunami killed more than 230,000 in a dozen countries across Asia.