The 64th session of the UN General Assembly kicked off its general debate on Wednesday and Ban Ki-moon called for unity through the United Nations to tackle multiple crises.

UN General Assembly President Ali Abdelsalam Triki hosts the general debate at the UN headquarters in New York, Sept. 23, 2009. The 64th session of the UN General Assembly kicked off its general debate on Wednesday. [Shen Hong/Xinhua]

In addressing world leaders gathered at UN Headquarters for theseven-day annual event, the UN Secretary General listed the crisesas the crises of food, energy, recession and pandemic flu, and said the time to act is now.

UN Secretary-General Ban Ki-moon addresses the general debate at the UN headquarters in New York, Sept. 23, 2009. The 64th session of the UN General Assembly kicked off its general debate on Wednesday. [Shen Hong/Xinhua]?

Ban said the world's most pressing challenges can only be solved when countries unite through the United Nations.

"If ever there were a time to act in a spirit of renewed multilateralism, a moment to create a United Nations of genuine collective action, it is now," Ban said.

"Now is our time. A time to put the 'united' back into the United Nations," he said. "United in purpose. United in action."

In his wide-ranging speech before dozens of heads of state or government, Ban was speaking to spotlight the need for joint action on issues ranging from climate change and disarmament to ensuring that the world's poorest people are not left behind by efforts to deal with the economic crisis.

The threat posed by climate change is the greatest challenge faced by humanity, he said, calling for united global efforts to tackle the problem.

President of the UN General Assembly Ali Abdelsalam Triki hosts the general debate at the gjzp001UN headquarters in New York, Sept. 23, 2009. The 64th session of the UN General Assembly kicked off its general debate on Wednesday. [Shen Hong/Xinhua]

Ali Treki, president of the 64th session of the UN General Assembly, said global challenges such as climate change, the economic, financial, food and energy crises can only be addressed through a well-functioning multilateral system.

"Multilateralism is the way forward to address global common-shared problems and it is also the only way to ensure effective and collective action," Treki said after Ban.

"As the embodiment of multilateralism, the United Nations is the most legitimate forum for ensuring concerted global action," he said, pledging to work with all 192 member states of the world body to "facilitate consensus on a revitalized General Assembly."

(Xinhua News Agency September 24, 2009)