White House launches push against sexual assault
Celebrities and musicians are among those joining the White House in a public drive to prevent sexual assault on US university campuses.
The "It's On Us" campaign is aimed at encouraging young men to intervene when they witness situations that could lead to a sexual assault.
The US estimates one in five women are sexually assaulted while in university.
Among the partners in the campaign is the US collegiate athletic association and several major media firms.
At a White House event on Friday launching the campaign, President Barack Obama said campus sexual assault was "an affront to our basic humanity".
"We still don't condemn sexual assault as loudly as we should," Mr Obama said. "We make excuses. We look the other way. The message that sends can have a chilling effect."
"It is on all of us to reject the quiet tolerance of sexual assault and to refuse to accept what's unacceptable," Mr Obama said.
"And we especially need our young men to show women the respect they deserve, and to recognise sexual assault, and to do their part to stop it."
In an advert unveiled online before the White House event, actor Jon Hamm, actress Kerry Washington, musician Questlove, basketball star Kevin Love and others urge viewers to intervene in situations that could lead to assault.
Benjamin Zand, BBC Pop-Up, Boulder, Colorado
With a US college population of nearly 20 million, this is a big issue for the White House. Colorado University-Boulder is on the list of colleges being investigated for their handling of rape complaints.
In Boulder, I've been hearing stories from women who have been sexually assaulted. Finding such cases has not been difficult. Another thing we're looking at is the culture on campus that allows assault to happen. That, as many women tell me, takes us to the fraternities.
Frat parties, alcohol and a machismo culture are widely blamed here. But trying to speak to fraternities to hear their views is near impossible. After numerous phone calls and door knocks, it's clear the frats do not want to talk.
It is a conversation they do not want to be part of, as it brings unnecessary attention. But they may be forced to address sexual assault sooner than they want.
They ask viewers to make sure friends get home safe and not to blame victims of sexual assault.
On the campaign's website, readers are asked for their name, email and post code as they pledge "not to be a bystander to the problem, but to be a part of the solution".
The information is collected by Generation Progress, the youth arm of the liberal Center for American Progress, which has close ties to the White House.
The message is largely targeted at men, the White House says, because research suggests men are often to reluctant to speak out against violence against women because they think other men accept it.
The advert and anti-assault messages will appear at arenas during National Collegiate Athletic Association (NCAA) championship sport events.
The campaign will also be promoted on the websites associated with younger people, including pop, hip-hop and country music channels.
Major video game publisher Electronic Arts will also encourage users to sign up for the campaign's pledge through its online platforms.
The campaign is a result of a task force launched by the White House in January.
The US Department of Education has named dozens of colleges and universities under investigation for mishandling of sexual assault cases.