We "call on all WTO members to demonstrate constructive flexibility to bring these negotiations to a prompt successful conclusion," the G8 leaders said in a statement after they wrapped up their annual summit in Germany's Baltic sea resort of Heiligendamm.

The G8 comprises the United States, Britain, Germany, France, Italy, Japan, Canada and Russia. The European Union is also represented in recent years.

As usual, leaders from major emerging economies of China, India, Brazil, Mexico and South Africa, attended the last-day meeting, which brought together nearly all trading powers in the World Trade Organization.

The G8 leaders noted that the six major WTO members had set the deadline to conclude the Doha-round talks within this year, a realizable goal which needs intensifying work.

In their latest effort to revive Doha round, trade ministers from the United States, the EU, Japan, Australia, India and Brazil agreed on the year-end deadline during their April meeting in New Delhi, India.

"We urge ministers in charge of trade, in particular from leading developed countries and major emerging economies, to provide in the coming weeks a solid platform for a multilateral negotiation leading to an agreement on modalities," the G8 leaders said.

The United States, the EU, India and Brazil were ready to work on their differences again in the middle of June.

The Doha-round talks, initially launched in 2001 with the aim of alleviating poverty through fairer trade practices, came to a deadlock in July 2006 due to sharp differences on agricultural trade and industrial market access among major WTO members.