Hollywood actor George Clooney, who recently received an Emmy for his humanitarian work to raise awareness about the crisis in Darfur, admits that his campaign has failed to halt the killings in the region.

The 'Ocean's Eleven' star has been extensively involved in raising awareness about the conflict in Sudan, where millions of refugees are said to have been killed since 2003.

Clooney was granted a private meeting with US President Barack Obama last year to talk about the 'Be A Voice For Darfur' scheme. The Sudanese government signed a ceasefire agreement with the Justice and Equality Movement (JEM) in February, but it hasn't stopped civilians being targeted.

Clooney terms the campaign 'greatest failure of my life', reports contactmusic.com.

'I've been honoured to be able to lend my celebrity status 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,' he said.

'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,' he added.