|Environmental organisations attending the conference have been cautiously optimistic [Reuters]
Delegates at the United Nations climate conference in Mexico were working beyond the scheduled close of the meeting in an attempt to salvage a deal after days of deadlock over emissions cuts.
After hours of talks behind closed doors on Friday a draft agreement had been drawn up, setting the goal of limiting global warming to less than two degrees Celsius and providing for the setting up of a global fund to help developing nations pay for the cost of climate change.
"We have seen remarkable progress," Patricia Espinosa, Mexico's foreign secretary, said as she sasked the delegates from almost 200 nations to consider the deal.
"We must continue ahead. We must recognise that these drafts represent real and very substantive progress."
The text pledges the creation of a $100bn annual "green fund" by 2020 for developing countries threatened by climate change and payments to protect tropical forests, as well as the temperature target.
The text says that the conference "recognises that deep cuts in global greenhouse gas emissions are required according to science ... with a view to reducing global greenhouse gas emissions so as to hold the increase in global average temperatures below two degrees Celsius above pre-industrial levels".
'No binding targets'
However, it does not set binding targets on reducing the so-called greenhouse gases that cause climate change.
The draft simply sets a target of working out a "global goal for substantially reducing global emissions by 2050".
A deal at last year's summit in Copenhagen had similar language, but was never approved by the full UN conference involving more than 190 nations.
"There's a basis there for actually moving forward," Stewart Maginnis, from the International Union for Conservation of Nature, told Al Jazeera.
"I think by and large we're a little bit more optimistic now than we were this morning."
Todd Stern, the US climate envoy, said: "What we have now is a text that is not perfect but is certainly a good basis for moving forward.
"This is the best product of a collective exercise."
But others were more sceptical of the 11th hour proposal.
"We have before us a document of `take it or take it'," Pablo Solon, Bolivia's chief negtiator, said.
"We won't sign a document that means an increase in the rise in temperatures when we already have 300,000 people dying every year."
However, the Bolivian objections were not enough to stop the deal geting preliminary approval, delegates said.
Al Jazeera's Craig Mauro, reporting from Cancun, said the draft document suggested that delegates were closing in on a compromise deal that would at least extend the Kyoto Protocol, which set reductions targets for 37 wealthy countries, beyond the end of its first term in 2012.
"The reason [the draft] is significant is that it includes a couple of things in the actual treaty which were not in there before, including a total range, aim, for reducing greenhouse gas emissions of all the signatories," he said.
The proposed document refers to "a second commitment period" for Kyoto.
In Kyoto in 1997, parties agreed on modest mandatory emissions reductions by richer nations, but the US alone in the industrial world, rejected the Kyoto Protocol, complaining it would hurt its economy.
Since then China has replaced the US as the world's biggest emitter, but it too has resisted calls that it assume legally binding commitments - not to lower its emissions, but to restrain their growth.
At Cancun such issues came to a head, as Japan and Russia fought off pressure to acknowledge in a final decision that they will commit to a second period of emissions reductions under Kyoto.
The Japanese complained that with the rise of China, India, Brazil and others, the 37 Kyoto industrial nations now account for only 27 per cent of global greenhouse emissions. They want a new, legally binding pact obligating the US China and other major emitters to cut greenhouse gases.
Details of many other issues also remained unclear as Cancun drew to a close, with much of the debate on Friday appearing to be on finding language to finesse irreconcilable views and buy another year until the next major congress in Durban, South Africa.
Oversight and financing of the $100bn Green Climate Fund, which is to aid developing nations obtain clean-energy technology for cutting their own greenhouse gas emissions and adapt to potentially damaging climate change, will be left to post-Cancun negotiations.
A UN advisory panel had suggested placing levies of some kind on the fuel or emissions of airlines and merchant shipping, but such a proposal was dropped during the negotiations.
Even the forestry programme, known as Reducing Emissions from Deforestation and Forest Degradation (REDD), which had been touted as one of the easiest potential deals at Cancun, met last-minute hurdles over how to make sure that the rights of indigenous communities were safeguarded.
Meanwhile, UN security personnnel clashed with protesters and journalists outside the conference.
The scuffles broke out when UN police arrived to break up a demonstration by a group of activists calling themselves "Youth Movement Against Climate Change".
Police forced the activists onto a bus and pushed photographers back, trying to stop some from taking pictures.