MONTERREY, Mexico -- Saying poverty fuels terrorism, dozens of world leaders launched a U.N. summit Thursday by promising to do more to help the world's neediest and end the cycle of economic chaos that plagues the developing world.

With the summit in northern Mexico, the gateway to Latin America, the reality of both financial crisis and terrorism hit close to home.

Argentine President Eduardo Duhalde lobbied international lenders to rescue his crippled economy, while Peruvian President Alejandro Toledo had to return home after a car bomb exploded outside the U.S. Embassy in Lima.

"We live in one world, not two," U.N. Secretary-General Kofi Annan told representatives from 171 countries. "No one in this world can feel comfortable, or safe, while so many are suffering and deprived."

While both the United States and Europe have promised billions more in aid in future years, their pledges still fall far short of the $100 billion a year the United Nations has said is needed to halve poverty by 2015. Throughout Thursday's meeting, leaders called on rich nations to do more.

"The world is standing on its head," Venezuelan President Hugo Chavez said. "World leaders need to set it straight."

Several leaders, arguing that helping poor nations is in rich countries' best interests, described extreme poverty and the growing gap between rich and poor as a major motivation for terrorism.

World Bank Director-General Mike Moore called poverty a "time bomb lodged against the heart of liberty," while the president of the U.N. general assembly, Han Seung-Soo, said the world's poorest areas are "the breeding ground for violence and despair."

"In the wake of Sept. 11, we will forcefully demand that development, peace and security are inseparable," Seung-Soo said.

Toledo, looking weary hours after a car bomb killed nine people in his country's capital, also linked poverty to violence. "To speak of development is to speak also of a strong and determined fight against terrorism," he said.