Sean Penn has opened fire on critics of his recent mercy mission to Haiti, stating that he hopes they all die of rectal cancer.

The controversial Milk star has been so caught up in the relief effort in earthquake-ravaged Haiti in recent weeks, he hasn't paid attention to what politicians and newsmakers have been saying about him.

But now that he's home, the 49-year-old can't believe his actions have upset so many people -- and he's disturbed that his critics can't just see the good in what he's trying to do in Haiti, where he helped establish a private relief organization.

In a taped TV interview, which will air this weekend on CBS News’ Sunday Morning, Penn rages, "Do I hope that those people die screaming of rectal cancer? Yeah. You know, but I'm not going to spend a lot of energy on it."

He isn't letting the criticism affect his plans to return to Haiti -- and he's taking his teenage kids with him: "They're gonna help... The first person served by service is the server. You know, there's nobody in the world that isn't looking for a kind of purpose in life, and tangible purpose is the most immediately recognizable."

And Penn insists his celebrity input is helping the people of Haiti: "We were able to get X-ray machines, and ventilators, and do all kinds of things."

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