Baku (AFP): The UN's climate chief urged G20 leaders on Saturday to push COP29 talks towards a deal to raise money for developing nations as diplomats struggled to find common ground in marathon negotiations.

Negotiators worked through the night in efforts to produce a new draft deal before ministers arrive next week for the final days of the COP29 talks in a Baku sports stadium, but differences remained.

"There is a long way to go, but everyone is very aware of the stakes, at the halfway point in the COP," UN climate chief Simon Stiell said in a statement.

Stiell appealed for leaders of the Group of 20, which includes the world's top economies and polluters, to weigh in when they meet in Brazil on Monday and Tuesday.

"As G20 Leaders head to Rio de Janeiro, the world is watching and expecting strong signals that climate action is core business for the world's biggest economies," Stiell said.

"G20 Leaders must signal loud and clear that international cooperation is still the best and only chance humanity has to survive global heating," he said.

Some developing countries, which are least responsible for global greenhouse gas emissions, want an annual commitment of $1.3 trillion to help them adapt to climate impact and transition to clean energy.

The figure is well above what donors including the United States, the European Union and Japan currently pay.

But the negotiations are stuck over a final figure, the type of financing, and who should pay, with developed countries wanting China and wealthy Gulf states to join the list of donors.

"We know we need at least 1.3 trillion to be committed to the low and middle income countries. And that has to be the figure at the end," Irish climate minister Eamon Ryan said earlier this week.

"The question is what's that made up of," he said.

Rich nations, which face their own economic challenges and political pressure following years of high inflation, are loath to commit large amounts of money from their public budgets alone.

Buried in debt, developing countries do not want the money to come in the form of loans.

'Much to do'
The latest draft deal was 25 pages long, and still contained a raft of options.

Samir Bejanov, deputy lead negotiator of COP29 host Azerbaijan, said nations were given more time to produce a new text later on Saturday.

"There is still much, much to do," Bejanov said in a press conference.

"Over the last few days, some people have doubted whether collectively we can deliver. It's time for the negotiators to start proving them wrong," he added.

Observers described a tense atmosphere in the negotiating rooms in Azerbaijan's capital.

"Stark divisions between North and South prevent negotiators from tackling the main issues at hand," said Iskander Erzini Vernoit, director of the Imal Initiative for Climate and Development, a Morocco-based think tank.

Tensions also emerged after some nations specified how much they should be getting from any deal.

A bloc of least-developed nations, mostly from Africa, asked for $220 billion while small-island states at threat from rising seas want $39 billion.

Friederike Roder, a vice president at the non-profit Global Citizen, said the latest draft contains a "jungle of options" that makes "insufficient progress or even backtracks" on some key points.

"What is urgently needed is real political momentum and energy from world leaders as they convene for the G20 summit in Rio," she said.