Leaders of the Group of Eight (G8) industrialized nations have gathered in Italy to evaluate the global economic downturn, whose "worst" political and social effects are yet to come.

The annual G8 summit, set against a backdrop of anti-G8 protests, will be held from Wednesday to Friday in the earthquake-hit city of L'Aquila, where nearly 300 people were killed in April.

But as G8 leaders and a host of emerging powers arrive at the city, World Trade Organization chief Pascal Lamy issued a stern warning of what they should expect when discussing the financial outlook, AFP reported.

"The worst of the crisis in social terms is still to come," Lamy said. "The worst of the crisis in political terms is still to come."

The bulk of the summit is likely to focus on efforts to shore up the economy, which traditionally gathers the eight leading economies -- Britain, Canada, France, Germany, Italy, Japan, Russia and the United States.

Last year at the Hokkaido summit in Japan, G8 leaders acknowledged a slowdown in global economic affairs but failed to grasp the significance of the situation that in just two months after the meeting began to unfold.

With the implosion of the investment bank Lehman Brothers, one of the most prestigious companies on Wall Street, the world braced itself for an era that is only being compared to the worst economic depression of the 1930s.

Although the group is now expected to take measures to tackle the crisis, the G8 countries seem to have lost their monopoly on the economy.

Instead, they will focus on an ambitious agenda marred by a variety of overshadowing issues.

UN chief Ban Ki-moon plans to press the G8 to live up to previous pledges on climate change. Analysts, according to the BBC, believe the leaders are likely to agree to cut greenhouse gas emissions by 50% by 2050 -- with rich nations reducing them by 80 percent.

Another animated discussion, which some African leaders are to join on Friday, is development aid and food security for areas of Asia and Africa.

The other topic, which is suggested to replace the finical crisis as the main item on the agenda, is foreign affairs -- such as recent developments in China and Iran.

Chinese President Hu Jintao, who was to be included as the leader of an emerging power in the G8 talks, changed his plans and returned home to deal with the outbreak of violence that has swept northwestern China.

The violence that erupted in China's oil-rich Xinjiang territory has so far claimed at least 156 lives.

Western leaders also plan to push the post-election crisis in Iran to the top of the agenda despite the reservations of China and Russia, AFP reported.

Iran has blamed foreign powers for protests and riots in the country following the landslide re-election of President Mahmoud Ahmadinejad.

The G8, however, will reportedly take a stance and warn Tehran that it cannot blame others for what happens on its soil.

The summit will first convene at 1100 GMT on Wednesday with discussions on financial regulations and the signs of an end to the recession.

At 1830 GMT, the group will talk about international issues with a statement expected on the topic at 2200 GMT.

MD/AA