BEICHUAN, China (CNN) -- A horrific scene emerged from the rubble of Beichuan Middle School Thursday, three days after a massive earthquake shook southwestern China to its core

Parents collapsed in spasms of agony as search teams pulled body after lifeless body from slabs of concrete and contorted metal, carrying them out on stretchers.

"There are teenagers wearing jeans and gym shoes and their bodies are twisted," CNN's John Vause said, reporting from just outside the school. "The expression on one girl's face was just pain -- she was dead."

Similar scenes unfolded across a vast expanse of southwestern China