AceShowbiz - George Clooney is frustrated his campaign to highlight the genocide in Darfur hasn't halted the ongoing killings - branding it "the greatest failure" of his life. The Hollywood actor has long been involved with raising awareness of the conflicts in the Sudanese region of Darfur, where millions of refugees have allegedly been killed since 2003.

He was even granted a private meeting with U.S. President Barack Obama last year to talk about the Be a Voice for Darfur scheme, which aimed to push the White House into taking action in the African region. The Sudanese government signed a ceasefire agreement with the Justice and Equality Movement (JEM) in February - but it hasn't stopped civilians being targeted.

And Clooney is saddened by the continued violence. He tells Britain's The Sun, "I've been honoured to be able to lend my celebrity to help wherever I can, especially on behalf of the United Nations. But in the case of Darfur, it's been the greatest failure of my life."

"With other people, we've been able to get a lot of attention focused on the terrible situation there and nothing has changed. It's very frustrating."