British Prime Minister Tony Blair expressed optimism on Thursday that an agreement on a need for "substantial" cuts in greenhouse gas emissions is possible at the end of the summit of the Group of Eight (G8) industrialized nations.

Blair was speaking to reporters after a meeting with U.S. President George W. Bush shortly before the G8 leaders started their first working session, which focuses on global economy.

"I think it's possible that we leave this summit with a commitment on the part of everyone to a substantial reduction in greenhouse gas emissions by 2050 as a global target."

"What's important is to get an agreement that there should be such a target and that's the sort of ballpark that we are talking about," he added.

For his part, Bush said it is too early to set numerical targets at the G8 summit in the German Baltic resort of Heiligendamm.

But he promised that Washington "will be actively involved if not taking the lead in a post-Kyoto framework."

The United States has been under attacks from Europe and environmental activists for not having taken stronger measures to tackle climate change.

Germany, which holds the rotating G8 presidency, has called for actions to limit the rise in global temperatures to two degrees Celsius this century and to cut carbon emissions by 50 percent below 1990 levels by 2050.

The United States voiced "fundamental opposition" to the German proposal.

Bush has announced a separate plan, calling on 15 of the world's biggest greenhouse gas producers to meet and agree on long-term goals by the end of 2008.

The United States, which has not signed the Kyoto Protocol, remains opposed to mandatory targets, citing that environmental protection cannot come at the price of hurting economic growth.

The G8 groups Britain, Canada, France, Germany, Italy, Japan, Russia and the United States.

The three-day G8 summit, which opened Wednesday night, is expected to focus on climate change, the development in Africa, the Doha Round of the World Trade Organization talks, the U.S. plans of deploying a missile defense shield in Eastern Europe.

The leaders may also talk about Iran's nuclear program and the security situation in the Middle East.

Bush, who has been engaged in a tense war of words with Russian President Vladimir Putin over the U.S. plans of deploying a missile defense shield in Eastern Europe, is expected to meet the Russian leader in the afternoon.

"I'm looking forward to my meeting with Vladimir Putin," Bush said along Blair after their meeting.

The Bush-Putin meeting has also been confirmed to Xinhua by a spokesman for the Russian delegation to the G8 summit.

Bush said he would try to convince and assure Putin that the missile defense system is aimed at "a rogue regime" -- not Russia.

Besides talks among themselves, the G8 leaders are scheduled to have two outreach sessions on Friday, one with five major developing countries -- Brazil, China, India, Mexico and South Africa, and the other with African countries -- Algeria, Ethiopia, Egypt, Ghana, Nigeria, Senegal and South Africa.

Source: Xinhua