U.S. Secretary of State Hillary Clinton has arrived in Haiti to inspect the damage from Tuesday's earthquake.
After talks with President Rene Preval, Clinton told Haitians the United States will ensure their country emerges "stronger and better" from the disaster.
"But I want to assure the people of Haiti that the United States is a friend, a partner, and a supporter, and we will work with your government under the direction of President Preval to assist in every way we can," Clinton said.
President Barack Obama has picked former presidents George W. Bush and Bill Clinton to lead a charity drive to help Haiti.
The UN has said the disaster is the worst it has had to deal with.
Interior Minister Paul Antoine Bien-Aime said 50,000 bodies had already been collected and that the final death toll will likely be between 100,000 and 200,000.
The Pan American Health Organization said a least eight hospitals and health centers in Port-Au-Prince had collapsed or been so damaged they were unable to function.