BLACKSBURG: President George W. Bush joined thousands of grieving Virginia Tech students and staff Tuesday at a memorial service to mourn 32 people killed in the deadliest US school shooting ever.   

Teary-eyed students hugged each other as they filed into the Cassell Coliseum, many wearing the school's orange and maroon colors amid tight police and secret service security.   

The Virginia Tech corps of cadets marched into the coliseum solemnly to a muffled funeral drum beat, while Bush and his wife Laura arrived later for the convocation.   

"I'm here to show my support for the victims and to stand together," said graduate student Kerri Symons, 21.   

Earlier, police identified Cho Seung-Hui, a 23-year-old student majoring in English, as the gunman behind the shooting at the university in Blacksburg, Virginia.   

He killed 30 people in a classroom building before turning the gun on himself, police said, adding that they suspect he had also killed two other people moments earlier in another campus building.