UNITED NATIONS - French President Nicolas Sarkozy on Monday pledged to boost aid to the world's poorest by 20 percent over the next three years and issued a plea for other developed nations to join him in meeting U.N. antipoverty targets by 2015.

With Millennium Development Goals, set by the United Nations 10 years ago, lagging and hit hard by the global recession, Sarkozy implored world leaders not to fall back into "old bad habits" of ignoring global poverty as the world economy begins climbing out of the severe economic downturn

"We have no right to do less than what we have decided to do," Sarkozy told the assembled leaders. He also said the world body should join in creating a small international tax on financial transactions that would go toward ending poverty and meeting other millennium goals.

Sarkozy said France currently donated 10 billion euros (about $13 billion) a year.

"The financial crisis is severe in the rich countries," he said. "It creates deficits. But its consequences are far worse for the poor countries."

U.N. Secretary-General Ban Ki-moon opened the three-day summit with a call to the assembled presidents, prime ministers, and kings to use their power to meet U.N. goals to help the world's poorest by 2015.

Ten years after world leaders set the most ambitious goals ever to tackle global poverty, they are gathered again to spur action to meet the deadline - which the United Nations says will be difficult, if not impossible, in some cases.

General Assembly President Joseph Deiss of Switzerland called the session to order, saying: "We must achieve the Millennium Development Goals. We want to achieve them. And we can achieve them."

For centuries, the plight of the world's poor had been ignored, but with the turn of the new millennium, leaders pledged to begin tackling poverty, disease, ignorance, and inequality.

Israeli President Shimon Peres said peace and full stomachs were key to erasing poverty.

"We share the burden of saving the world from war and hunger," he said. "Without peace, poverty will remain. Without food, peace will not prevail."

World leaders have vowed to reduce extreme poverty by half, ensure that every child has a primary-school education, halt and reverse the HIV/AIDS pandemic, and reduce maternal mortality by three-quarters and child mortality by two-thirds. Goals additionally called for cutting by half the number of people without access to clean water and basic sanitation - all by 2015. They also set goals to promote equality for women, protect the environment, increase development aid, and open the global trading and financial system.

"We brought new urgency to an age-old mission," the secretary-general told the assembled leaders. "And now, we have real results. New thinking and pathbreaking public-private partnerships. Dramatic increases in school enrollment. Expanded access to clean water. Better control of disease. The spread of technology - from mobile to green."

But Ban called the advances "fragile" and declared, "The clock is ticking, with much more to do."

He urged the leaders to deliver the needed resources "above all by exercising political leadership."

"Despite the obstacles, despite the skepticism, despite the fast-approaching deadline of 2015, the Millennium Development Goals are achievable," the secretary-general said.

The summit will be followed by the annual ministerial meeting of the General Assembly, so leaders will be presenting positions not only on global antipoverty plans but also on global issues.

Amnesty International, which says world leaders have failed more than a billion of the world's poorest people, planned to unveil a Maternal Death Clock in Times Square on Monday to count maternal deaths around the globe while world leaders are meeting.

Maternal mortality remains unacceptably high and the clock will begin at 5,317,280, the number of women Amnesty says have died since the MDGs were adopted in September 2000. It predicted about 3,700 more would die during the summit, which ends Wednesday.