In what appeared to be a veiled swipe at the United States, though it was not explicitly named, the leaders called on Wednesday on rich countries to fight terrorism and instability by sharing their wealth, rather than through military intervention.
The most basic right of all humanity, said Brazilian President Luiz Inacio Lula da Silva, is to eat three decent meals a day.
"Hunger is actually the worst weapon of mass destruction. It claims millions of victims each year," Silva said. "There will be no peace without development and no development without social justice."
Tanzanian President Benjamin Mkapa argued that expanding global trade would not aid peace "when people are impoverished, hungry and angry."
"Anger will not yield to military interventions," Mkapa said.
The three-day World Bank gathering in Shanghai is focused on finding ways to make better use of the scarce resources spent on poverty relief in a world where about 2.8 billion people live on less than US$2 a day.
"We have to search for what works and what produces results," Mkapa said.
Developing nations need more debt relief, better access to world markets for their commodity exports and a larger share of resources if economic growth is to benefit all, he said.
Brazilian President Luiz da Silva
says hunger is biggest WMD
In Tanzania, 35% of the population is considered poor in terms of basic needs and 19% food-poor. Recent plunges in coffee prices mean that "many families that had never known abject poverty now do," Mkapa said.
"Democracy and open markets are only judged by what they deliver, not what they promise," he added.
Silva reiterated calls from Brazil and other developing nations for industrialised countries to end agricultural subsidies and barriers to exports from developing nations that he said put farmers in poor countries at a disadvantage.
"We cannot allow cows to get US$2 subsidies a day while half the world survives on even less than that," he said.
Chinese Premier Wen Jiabao, as host of the conference, pledged more aid for other developing nations and noted China's own goal of eliminating within the next decade the poverty that still afflicts 29 million of its own people.
Tanzanian leader Benjamin Mkapa
is critical too
While urban incomes in China now average about US $1,000 a year, in the countryside they still average just more than US $300.
Wen reiterated a recent pledge by Beijing of US $30 billion to the Asian Development Bank to help some of its poorest neighbours - China's first donation to a multilateral institution after many years as a major borrower.
China has long provided aid to its allies, many of them in Africa and Asia, and has also forgiven hundreds of millions of dollars in debt - a strategy that has enhanced Beijing's stature as a leader among developing nations.
"Developing nations must cooperate in pushing ahead development," Wen said. "Ending poverty is an ideal shared by all humanity. All nations have a deep responsibility for this."