L'Aquila, Italy  - The leaders of the world's top developed and developing powers began talks in the mediaeval Italian town of L'Aquila on Thursday in a search of agreement on liberalizing global trade and fighting global warming.

The meeting comes a day after the Group of Eight (G8) leading developed economies called for a "rapid, ambitious, balanced and comprehensive conclusion of the Doha Development Agenda" based on a "strengthened dialogue with our major partners."

European Commission President Jose Manuel Barroso, a regular G8 attendee, said that he wanted a successful conclusion to the Doha round of World Trade Organization (WTO) talks, which started in 2001, no later than 2010.

The talks hit deadlock in July 2008 in a row between the United States and India over agricultural trade.

The US is a permanent G8 member, alongside Britain, Canada, France, Germany, Italy, Japan and Russia.

The G8 leaders opened talks on Thursday with their counterparts from Brazil, India, Mexico, South Africa and Egypt. China's President Hu Jintao had also been set to attend, but was forced to fly home to confront ethnic riots in the province of Xinjiang.

Their talks were set to focus on trade, agricultural aid, and "future sources of growth" such as climate-friendly industry, according to the Italian government, which hosted the summit.

On Thursday afternoon, the G8 and G5 leaders were set to be joined by their counterparts from Australia, Indonesia and South Korea in the Major Economies Forum (MEF) to discuss climate change.

On Wednesday, G8 leaders agreed that world climate change should be limited to 2 degrees centigrade above pre-industrial levels to prevent catastrophic weather changes; that world greenhouse-gas emissions should fall by 50 per cent by 2050; and that they themselves should cut emissions by 80 per cent by the same deadline.

G8 leaders said they hoped the MEF meeting would endorse those goals as the foundations of an international deal on fighting climate change at United Nations talks in Copenhagen in December.

But G5 diplomats said that they would not accept the reference to worldwide emissions cuts at this stage, as this could prejudice the Copenhagen talks.

G8 leaders are therefore targeting MEF approval of the 2-degree cap for climate change as the main goal of Thursday's meeting. (dpa)