The US state of Virginia is observing a day of mourning for the victims of Monday's gun rampage at Virginia Tech university in which 33 people died.
The tributes moved many visitors to tears
A moment of silence was held in the state at noon local time (1600 GMT), and vigils and prayers have been organised across the country.
Meanwhile police are said to be making "great progress" in determining why gunman Cho Seung-hui did the killings.
Also, an independent panel will examine how authorities reacted to the crisis.
The six-member team includes former homeland security chief Tom Ridge.
Officials have been accused of ignoring signs that Cho, who had been identified as mentally ill, was a danger.
Orange and maroon
Students, staff and visitors observed a moment's silence in the Drill Field, in the university grounds, and bells rang out in honour of the victims.
Many donned the university's orange and maroon colours for the ceremony.
Many mourners wrote messages on special boards at a makeshift memorial in the university grounds, and some visitors cried on reading them.
A similar ceremony was being held in the state capital Richmond, attended by state governor Timothy Kaine.
The memorial day coincides with the eighth anniversary of the Columbine High School massacre in Colorado, in which 13 people died along with the two killers.
Colorado's governor Bill Ritter asked state residents to join in the silence for the Virginia Tech victims.
The first Virginia funeral ceremonies, for two international students among the dead, were held on Thursday.
Egyptian Waleed Mohammed Shaalan and Indonesian Partahi Lumbantoruan, both doctoral civil engineering students, will also have funeral ceremonies in their home countries.
On Friday, family members gathered in Israel for the funeral of mathematics professor Liviu Librescu.
Two people were killed at the West Ambler Johnston Hall, a university dormitory, at 0715 on Monday.
Two hours later Cho killed 30 students and teachers, plus himself, at the Norris Hall complex across campus.
Questions are being asked about the response to the first shootings and whether putting the campus on a full lockdown earlier could have saved lives.
Police spokeswoman Corinne Geller told the Associated Press news agency investigators were "making some really great progress" in determining how and why the killings happened.
They hoped to have something to tell the public next week, she said.
In conjunction with the police investigation, a panel, led by former Virginia police chief Gerald Massengill and including security and education officials and a psychiatrist, will study what mental health treatment Cho received and if more could have been done to avert Monday's violence.
Police have already revealed that Cho, who moved to the US with his family from South Korea in 1992, was admitted to a mental health unit in late 2005.
In the aftermath of the shootings, teachers and fellow students have spoken of Cho's extreme moods, violent writings and unpredictable behaviour.
In the two-hour lull between killings, Cho sent a package to US network NBC containing 28 video clips 1,800 words of text and 43 photos, 11 of them showing Cho aiming handguns at the camera.
Police have criticised the decision by NBC to air the clips.