Rescue workers used excavators Thursday to pull out victims, some screaming in pain, from the heavy rubble of buildings felled by a powerful earthquake that killed at least 529 people. The death toll was expected to rise. The brunt of Wednesday's 7.6-magnitude earthquake, which originated in the sea off Sumatra island, appeared to have been borne by Padang town where 376 people were killed. Four other districts accounted for the remaining deaths. The region was jolted by another powerful earthquake Thursday morning, causing damage but no reported fatalities. More than 500 buildings including hotels, schools, hospitals and a mall were destroyed or damaged in Padang. Thousands of people were believed to be trapped in the rubble. “Oh God, help me! help me!” Friska Yuniwati, a 30-year-old woman, screamed in pain, as she was carried to an ambulance in downtown Padang. She had been pulled out minutes earlier from the rubble of a house, her face covered in bruises and eyes shut. A total of 529 people were confirmed dead and 440 were seriously injured, the Social Affairs Ministry's crisis center said. Thousands were believed trapped, said Rustam Pakaya, head of the Health Ministry's crisis center. Terrified residents who spent a restless night, many sleeping outdoors, were jolted by the new quake Thursday morning. Parents of missing students stayed up all night, waiting for signs of life. “My daughter's face keeps appearing in my eyes ... my mind. I cannot sleep, I'm waiting here to see her again,” a woman who identified herself only as Imelda told TVOne, tears rolling down her face. She said her 12-year-old daughter Yolanda was in the school for science lessons. Meanwhile, Samoans sifted the wreckage of their flattened homes and told of being trapped underwater or flung inland by a tsunami that ravaged towns and killed at least 150 people in the South Pacific. The day after the disaster struck, officials were expecting the death toll to rise as more areas were searched. “To me it was like a monster – just black water coming to you. It wasn't a wave that breaks, it was a full force of water coming straight,” said Luana Tavale, an American Samoa govt staff.