WASHINGTON - The White House on Tuesday unveiled a celebrity public-service announcement, a website - NotAlone.gov - and a series of recommendations aimed at lowering the alarming rate of sexual assaults on campus.

The action came as Vice President Biden said officials at colleges and universities, even if they fear their schools' reputations may be damaged, "can no longer turn a blind eye and pretend rape and sexual assault don't occur on their campuses."

"Colleges and universities need to face the fact of what exists on their campuses," he said. "They need to step up to it."

The first report of the White House Task Force to Protect Students from Sexual Assault estimates that one in five women are sexually assaulted while in college, most often in the freshman or sophomore year. In the majority of cases, it is by someone the woman knows.

Biden said only 13 percent of women attacked report the crime to their schools.

"They fear they'll be shamed," he said. "They're embarrassed. Or scared they won't be safe on campus with their attacker roaming around or maybe sitting in the same history class."

The suggested steps include identifying the scope of the problem on individual campuses, helping prevent assaults, helping schools respond effectively, and making the federal government's enforcement efforts more transparent.

The recommendations were put forward after three months of 27 sessions with more than 2,000 people who made suggestions.

The administration plans to hold more listening sessions and revise the report.

The public-service announcements - featuring, among others, Daniel Craig, Seth Meyers, Benicio Del Toro, and Steve Carell - encourage men to speak up and step in if they see someone in danger of being sexually assaulted.