U.N. Secretary-General Kofi Annan (search) appealed to world leaders Tuesday to expand the Security Council with a view to making the 15-member panel more effective and representative of 21st century "geopolitical realities."

Opening a meeting of the U.N. General Assembly (search), Annan challenged the 191 U.N. member states to re-examine the way the council -- whose five permanent members decide virtually all outcomes -- deals with conflicts.

His call for broader representation was echoed by French President Jacques Chirac (search), Brazilian President Luiz Inacio Lula da Silva, and Japan Foreign Minister Yoriko Kawaguchi.

There is an "urgent need for the council to regain the confidence of states and of world public opinion -- both by demonstrating its ability to deal effectively with the most difficult issues, and by becoming more broadly representative of the international community as a whole, as well as geopolitical realities of today," Annan said.

The Security Council became a battlefield of divergent opinions as the United States pushed for U.N. authorization of the war in Iraq, then sought legitimacy from the world body for its occupation.

The United States clashed repeatedly with France, Russia and Germany over Iraq and the prolonged wrangling took up most of the council's time and attention in the months ahead of the invasion and after.

Although all 15 council members were involved in deliberations on Iraq, the final stance depended on compromises reached among the United States, France, Britain, Russia and China -- the veto-holding members.

Many countries, which were either not on the council or were among its 10 elected members, felt ignored as the rich and powerful countries decided policies that bore the stamp of the United Nations and consequently that of international public opinion.

Now as the new session of the General Assembly opens, the attention remains focused on meetings on the sidelines between President Bush, Chirac and German Chancellor Gerhard Schroeder over a political role for the United Nations in Iraq.

The United Nations was founded in 1945 when there were just 51 members. The Security Council was given the primary responsibility of preserving peace and it has the power to enforce measures.

The expansion of the Security Council has been on the U.N. reform agenda for more than a decade and even the five permanent members have been open to discussing it. But there are major obstacles to council reform, not only on how large the council should be, but what countries should be permanent members, and which should have veto power.

Countries including Japan, Germany, India and Brazil have clamored to be part of a reorganized council that would provide greater representation to regions and developing countries.

Japan has demanded a permanent seat, saying its voice in the United Nations should reflect its status as the second-largest financial contributor to the United Nations.

On Tuesday Annan told the assembled leaders: "If you want the council and the council's decisions to command greater respect, particularly in the developing world, you need to address the issue of its composition with greater urgency."

Kawaguchi agreed, saying that if the council is not reorganized "the United Nations' ability to respond adequately to the new and complex challenges will be seriously questioned."

Chirac called specifically for the inclusion of Germany and Japan, given their economic clout, and said France could foresee Asian, African or Latin American countries taking a seat.

Later, he mentioned India as a possible permanent candidate. "Now it's very hard to imagine how one could exclude India from the possibility of having a permanent seat in Security Council given its characteristics," he said at a news conference.

"The Security Council was established at a time when there were 50 or so members ... it's not the same type of organization anymore," he said. "There are countries that were unknown that have become very important for political reasons, demographic reasons, economic reasons."

In a report released ahead of the General Assembly session, Annan said all states need to take a hard look at whether the United Nations and other international institutions need "radical reform" to cope with challenges ranging from combating terrorism and weapons proliferation to eradicating poverty and safeguarding human rights.

As the General Debate opened, Brazil's Silva was the first to demand a reorganized council.

"More specifically, it must take into account the emergence in the international scene of developing countries," he said. "They have become important actors that often exercise a critical role in ensuring pacific settlement of disputes."

Switzerland's President Pascal Couchepin also backed an enlarged council.

"This could be done without harming its effectiveness as long as the increase in the number of members remains within reasonable bounds," he said.