BLACKSBURG, Va. — Representing America's anguish, President Bush told Virginia Tech students and teachers at a somber convocation Tuesday that the nation was praying for them and "there's a power in these prayers."

"It's impossible to make sense of such violence and suffering," Bush said at a memorial service on the campus where 33 people, including the suspected gunman, died in shootings Monday.

"Those whose lives were taken did nothing to deserve their fate," the president said. "They were simply in the wrong place at the wrong time. Now they're gone — and they leave behind grieving families, and grieving classmates, and a grieving nation."

Before flying to the tragedy-stricken university in southwestern Virginia, Bush ordered flags flown at half staff and issued a written proclamation in honor of those killed and wounded.

Speaking to a solemn crowd at a basketball arena, packed with students and others, many wearing orange short-sleeved Virginia Tech T-shirts, the president quoted a recent graduate blogging about the killings to encourage those who grieve to reach out for help.

"To all of you who are OK, I'm happy for that," Bush said, quoting the Internet posting. "For those of you who are in pain or who have lost someone close to you, I'm sure you can call on any one of us and have help anytime you need it."

The memorial service was subdued but ended with a spontaneous school chant of "Let's go, Hokies!"

The president met with a wounded student and 50 relatives of the victims, hugging them and telling them to take comfort from one another.