By NOMAAN MERCHANT and TIM TALLEYMOORE, Okla. (AP) â¿¿ Search and rescue crews worked through the night after a monstrous tornado barreled through the Oklahoma City suburbs, demolishing an elementary school and reducing homes to piles of splintered wood. At least 51 people were killed, including at least 20 children, and those numbers were expected to climb, officials said Tuesday. The storm stripped leaves off trees and left scores of blocks in Moore barren and dark. Rescuers walked through neighborhoods where Monday's powerful twister flattened home after home, listening for voices calling out from the rubble. A helicopter buzzed above, shining lights on crews below. As Monday turned into Tuesday, the town of Moore, a community of 41,000 people 10 miles south of the city, braced for another long, harrowing day. "As long as we are here ... we are going to hold out hope that we will find survivors," said Trooper Betsy Randolph, a spokeswoman for the Oklahoma Highway Patrol. More than 120 people were being treated at hospitals, including about 50 children. Amy Elliott, spokeswoman for the Oklahoma Medical Examiner's Office, said Tuesday that there could be as many as 40 more fatalities from Monday's tornado. On Monday evening, families anxiously waited at churches to hear if their loved ones were OK. A man with a megaphone stood near St. Andrews United Methodist Church and called out the names of surviving children. Children and parents hugged as they reunited. Other parents waited, hoping to hear their sons' and daughters' names as the night dragged on. Crews continued their desperate search and rescue effort throughout the night at Plaza Towers Elementary, where the storm had ripped off the school's roof, knocked down walls and turned the playground into a mass of twisted plastic and metal as students and teachers huddled in hallways and bathrooms.