India last night rejected a European roadmap to a new single, legally-binding agreement to revive the stuttering UN climate talks.

Using robust diplomatic language, environment minister Jayanthi Natarajan challenged rich countries to ratify a second commitment period of the Kyoto protocol (KP), and pay what they had promised to developing countries before trying to negotiate a new deal.

The comments came ahead of a meeting between Europe, the Basic countries - India, China, Brazil and South Africa - and the US to try to win support for the EU's proposal to try to negotiate a new legally binding treaty by 2015 that would take effect in 2020.

China has been ambiguous on whether it will support the EU, while Brazil said it was still in discussions. South Africa's president referred to the roadmap in his speech but did not commit to it.

The group of four powerful "Basic" countries put pressure on Europe by claiming that developing countries had pledged to cut more emissions than the rich and the onus should now be on them to make deeper cuts.

"It is time that the developed countries stepped up to fulfil their part of the [legal] commitment under Kyoto. There is an ambition gap because Kyoto partners have not fulfilled their political obligations," said Natarajan.

In a clear reference to Canada, Russia and Japan, she said: "There are more countries in the wings preparing to announce their intention to forsake their international obligation."

Natarajan's defence of Kyoto was backed by China. "A second commitment period is a must. Kyoto should be continued. Developed countries should honour their commitments," said Xie Zhenhua, head of Chinese delegation at Durban.

India's continued hostility to the EU proposal was underlined when Natarajan suggested the EU's proposal was unclear. "I have come to Durban with an open mind. But I would like to know whether [the proposal] would be binding only for mitigation and whether it will be same for Annex-1 [industrialised] and non-Annex1 [developing] countries. Commitment for finance and technology, whether it will be present or not, how will equity figure in such an agreement, how will [intellectual property rights] be handled."

But the EU challenged India to outline an alternative that would harness the emissions of leading economies. Isaac Valero Ladron, spokesman for the EU environment commissioner Connie Hedegaard, said: "Will India take on the responsibility of being a major economy, to give a clear political signal that it will commit in the future? This is the question that should be answered in Durban. If they say no to the roadmap, what are they going to do? What is the alternative they are positing? Major emitters, developed and developing, should say here in Durban when they will be ready for a legally binding agreement."

To bolster its argument that rich countries must do more, India referred to a recent study by the Stockholm Environment Institute of the pledges made last year in Cancún by all countries. It shows that developing countries are pledging 30%-50% more cuts than the rich, and that the rich may be able to avoid taking any action whatever to meet their pledges by taking advantage of accounting loopholes.

Sivan Kartha and Peter Erickson of the Stockholm Environment Institute (SEI) said: "Developing countries pledges amount to more absolute mitigation than all developed countries. Unless accounting rules for Annex 1 countries are made more stringent, then Annex 1 countries will be able to formally comply with their pledges with very little actual mitigation and possibly none at all."

Kartha and Erikson reviewed four recent detailed studies of countries' mitigation pledges under the Cancún agreements and concluded that these would lead to a 3-5C rise. They conclude that under both high and low growth conditions, and with both lax and lenient rules, developing countries had so far pledged to cut much more than rich countries.

The figures are significant because they undermine the EU's insistence that a new legally binding agreement is needed to get developing countries to cut emissions further.

But Hedegaard suggested that China was still not pledging enough to meet the conditions under which the EU would agree to sign up to a second commitment period of the Kyoto protocol.

"I still believe that China holds one of the central keys to unlock the situation. The EU is willing to take a second Kyoto period, but the central issue remain how China will follow us and when. Here more clarifications and further dialogue are needed."

Major developed countries also suggested reports that the Chinese had swung in favour of a new legally binding deal were wrong.

"China has always said it is in favour of a legally binding deal – that binds developed countries to make emissions cuts. It is certainly not clear that they are now saying they will take on international legally binding targets on the same basis [as developed countries], which is what we're talking about here," said one participant who could not be named.

Todd Stern, the US special envoy for climate change, cast doubt on whether China was showing greater flexibility in its position, as the UK had suggested. Fresh from a meeting with the Chinese minister Xie Zhenhua, he told a press conference: "It's not my impression that there has been a change at all in respect to a legally binding agreement. I did not understand [from] Mr Xie that there was any change."

The Greenpeace UK chief policy adviser, Ruth Davis, said: "The EU needs to stand firm and refuse to back down on its demand that we get a legal deal in 2015, but it will need the help of the hosts South Africa. That's what the vast majority of countries here want to see happen."