The US university where 32 students and staff were killed in a gun rampage has held its annual graduation ceremony.
Relatives of the 27 slain students are receiving posthumous degrees
Thousands of students were honoured at Virginia Tech, where student Cho Seung-hui, 23, went on a shooting spree before killing himself.
Some 5,000 students graduated at the ceremony, attended by 30,000 people.
The 27 dead students are receiving posthumous degrees, and diplomas will be handed out at smaller ceremonies in individual colleges on Saturday.
"Our hearts are saddened and our minds are troubled," Virginia Tech President Charles Steger said in an address to the graduates on Friday.
The former commander of US armed forces in the Middle East, Gen John Abizaid, whose son attends the university, was the keynote speaker.
"While we are saddened by the loss of those who cannot be here today, I believe that they would want this ceremony to commemorate both the tragedy of yesterday and the promise of tomorrow," he said.
Security at the university in Blacksburg was heightened for the graduation weekend, with extra police deployed at the campus.
"Virginia Tech remains under a state of alert since April 16th," said spokesman Mark Owczarski, adding that the visible police presence brings a "sense of safety and protection".
In addition, he said Gen Abizaid "brings with him a degree of security".
Student Andrea Falletti, who received a degree in business management, said she would not let recent events overshadow the importance of the day.
The gunman, Cho Seung-hui, was a student at the university
"Obviously, what has happened has affected everything in our lives, and it will affect graduation," she told AP news agency.
"In a way, it's not going to be celebrating us as much - it's more about what we've done as a community. But that's OK. I'm proud of what we've done here."
In Washington, President George W Bush issued a statement praising "the compassion and resilient spirit" of the university community
"Laura and I salute the Virginia Tech Class of 2007. We also remember the students and teachers whose lives were taken last month," he said.
"They will always hold a special place in the hearts of this graduating class and an entire nation."
Cho killed 30 students and teachers, plus himself, at the university's Norris Hall complex on 16 April. He is also assumed to have killed two others at a university dormitory two hours earlier, as the same gun was used at both locations.