UNITED NATIONS — President Barack Obama unveiled to world leaders on Wednesday a new plan for distributing U.S. aid to struggling nations, promising to “”change the way we do business”” by putting a new focus on self-reliance and market forces to create a path out of poverty.

The United States’ aim is not to simply dole out aid but to create “”the conditions where assistance is no longer needed,”” Obama said in comments at the United Nations. The program will reward countries willing to cooperate in their own improvement, he said.

At the same time, Obama insisted that the United States will not abandon the helpless and would remain a leading world donor. Countries such as Haiti and Afghanistan will continue to receive special assistance, even if their governments’ records of reform are open to question, aides said.

“”We will seek partners who want to build their own capacity to provide for their people,”” Obama said. “”We will seek development that is sustainable … The days when your development was dictated in foreign capitals must come to an end.””

Obama spoke during a week in which world leaders have been focused on the U.N.’s chief anti-poverty program, the Millennium Development Goals, a 15-year plan launched in 2000. With five years left to meet targets of poverty reduction and health care improvements, and amid a world economic crisis, doubts have spread about its ultimate success.

The new U.S. program, set up after a lengthy review, builds on the Bush administration’s Millennium Challenge Corporation concept, which aimed to give special rewards to countries that seek to improve their own development and governance in specified ways.

Aides to Obama acknowledged that the new approach will mean shifting aid from some countries to others, but were vague on who will be cut back.

The president named a few names. Obama singled out Tanzania as a country that the U.S. will reach out to help, and mentioned the African coastal country of Cote d’Ivoire as one that may not meet the new American criteria for assistance.

He said the new program would put a strong emphasis on broad economic growth, which he hailed as “”the most powerful force the world has ever known for eradicating poverty and creating opportunity.””

He said economic growth had turned South Korea “”from a recipient of aid to a donor of aid. It’s the force that has raised living standards from Brazil to India. And it’s the force that has allowed emerging African countries like Ethiopia, Malawi and Mozambique to defy the odds and make real progress toward achieving the Millennium Development Goals, even as some of their neighbors — like Cote d’Ivoire — have lagged behind.””

In regions where problems are less acute, such as Eastern Europe and Latin America, Obama aides said help is likely to be reduced, while the poorest stretches of Africa and Asia may get more aid.

Aides said that the United States has often seemed to simply throw its money at problems. Obama has promised to double foreign aid to $50 billion by 2012, but also wants to make the programs more effective.

A consensus has developed among major donor nations, mainly that money must be spent on more than food, health and education, and also should help build economies and public institutions.

The president’s tough-love message echoed those of other world leaders in New York for the annual United Nations General Assembly. German Chancellor Angela Merkel has called on poorer nations to take greater responsibility for their progress, while Canadian Prime Minister Stephen Harper urged greater accountability from countries that receive aid each year.

The leaders’ remarks reflect the concerns of donor nations about the stewardship of their contributions, exacerbated by global economic troubles and the drive for austerity. But hard times weigh on the recipient nations, too. Leaders from African nations are seeking a greater commitment to help their continent climb out of poverty.

Private aid groups have heard American leaders talk about focusing their aid before, but experts consider Obama’s new strategy somewhat sweeping in its goals.

The president seems to be proposing a more comprehensive approach than has been at work in the past, said Mark Quarterman, director and senior adviser of the Post Conflict Reconstruction Project of the Center for Strategic and International Studies.

The actual effect depends on the criteria for implementation, Quarterman said.

“”We can only have a sense of how the practice of development would change with more details,”” Quarterman said. “”It will be important to how the process of a comprehensive development approach would be organized within the government. The idea sounds very interesting, and U.S. foreign assistance needs an overhaul, but the devil really is in the details.””