The two rappers announced their joint donation Thursday, saying they hoped to inspire others, especially blacks, to give.
"This is our community," Shawn "Jay-Z" Carter, who is also president and CEO of the Def Jam record label, told The Associated Press by phone. "When I turn on CNN, I see a lot of black people on the streets. I know it's other people too, but those projects have been hit hard."
Combs agrees. "We are all descendants from each other's families. When you hear black people say 'brothers' and 'sisters,' it's really true. These are all people that I know I'm related to somehow, some way — the human race family."
Former New Orleans Mayor Marc Morial, now president of the Urban League, said Thursday that those left in the city "are people who are African-American mostly but not completely, and people who were of little or limited economic means. They are the folks, we've got to get them out of there."
Jay-Z said he had put in calls to NBA star LeBron James and rapper Kanye West for donations.
Also on Thursday, Celine Dion and the partners of her Las Vegas show, "A New Day" — companies Concerts West/AEG Live and Dragone — pledged a $1 million donation to the Red Cross Disaster Relief Fund.
And Oscar-winner Nicolas Cage, who has a home in New Orleans, donated $1 million Thursday to the American Red Cross for hurricane relief efforts for ravaged New Orleans, a spokeswoman said.
In his statement, his publicist, Annett Wolf, said Cage "wishes to help his neighbors during this most devastating time."