Envoys from the 20 countries, which are together responsible for 80 per cent of the world's emissions blamed for global warming, were trying to bridge gaps on what to do after Kyoto's obligations expire at the end of 2012.

'We reconfirmed the principle of common but differentiated responsibility in negotiating the next deal for 2013 and onward,' said Japan's Environment Minister Ichiro Kamoshita, the co-chair of the weekend talks in suburban Tokyo.

'It was made clear that there are a variety of positions among developed countries, emerging countries and developing countries,' he said.

A UN climate conference in December in Bali set a deadline of the end of 2009 for a post-Kyoto deal. The next negotiations start at the end of the month in Bangkok.

'The talks here are very useful, because this is the first opportunity after the Bali meeting,' said Halldor Thorgeirsson, director of the Bali roadmap for the UN climate body, told AFP.

But disagreements were out in the open with developing countries insisting that they not be held up to the same targets as wealthy nations in slashing emissions.

The United States has shunned the Kyoto Protocol, saying it is unfair by making no demands of developing nations. But virtually all countries agreed in Bali to take part in negotiating Kyoto's successor.

Japan, which lags behind in meeting its own Kyoto targets, has like the United States been lukewarm on EU-led calls to set further broad binding targets for each nation.

Japan pushed at the conference for a 'sectoral' approach - setting energy efficiency goals for each industry - but met with scepticism from developing countries.

Mr Kamoshita defended Japan's position, saying: 'Our proposal was meaningful in that it showed a new idea that's different from emission targets for each nation' championed by the European Union.

South Africa was particularly vocal against the Japanese proposal.

'It is clear that developed and developing countries are still far apart on sectoral approaches,' South African Environment Minister Marthinus van Schalkwyk said.

But he said that some of the developing nations' concerns were addressed by the end of the talks.

'South Africa understands the urgency of action,' he said. 'As a developing country, we stand ready to contribute our fair share in a climate regime.'

Alden Meyer, the strategy director for the Union of Concerned Scientists, said he had worried that Japan's promotion at the conference of sector-specific targets may 'impede the momentum that we had from Bali.' But in the end, 'many constructive ideas were put on the table,' he said.

Former British prime minister Tony Blair, who is tasked with bridging differences in talks, had opened the conference with an impassioned call for developing nations to join the rich world in steep binding cuts.

Japan in July hosts the Group of Eight summit of rich nations - Britain, Canada, France, Germany, Italy, Japan, Russia and the United States - which it hopes will make progress in a climate deal.

'Japan's role as the (G8) host will be how to coordinate these opinions. And I think what's important is how Japan can send a message that strengthening support to developing countries is important,' Mr Kamoshita said.

'Also important is how the G8 members can go further to achieve our current emission cuts targets, and what we can do to realise the long-term goal of halving the global emission by 2050,' he added.

Last year's G8 summit in Germany said rich nations would 'seriously consider' slashing emissions by half by 2050. But there was no binding commitment and the base year was vague. -- AFP