BAKU, Azerbaijan (AP) — The United Nations' annual climate talks pushed into overtime Saturday under a cloud of anger and disappointment as negotiators were well short of a deal on money for developing nations to curb and adapt to climate change.

A draft of the final agreement Friday pledged $250 billion annually by 2035, more than double the previous goal of $100 billion set 15 years ago but far short of the annual $1 trillion-plus that experts say is needed. Through the early hours of Saturday morning, The Associated Press saw lead negotiators from the European Union, the United States and other nations going through the empty halls from meeting to meeting as delegates tried to hash out a new version of the deal.

“We're still working hard,” U.S. climate envoy John Podesta told the AP past 4 a.m. local time.

The climate talks, called COP29, in Baku, Azerbaijan, were scheduled to end Friday. Workers have already begun dismantling the venue for the talks.

A climate cash deal is still elusive at the talks

Wealthy nations are obligated to help vulnerable countries under an agreement reached at these talks in Paris in 2015. Developing nations are seeking $1.3 trillion to help adapt to droughts, floods, rising seas and extreme heat, pay for losses and damages caused by extreme weather, and transition their energy systems away from planet-warming fossil fuels and toward clean energy.

Representatives of some of the nations that are obliged to contribute the cash said the $250 billion climate finance figure is realistic and reflects their limits at a time when their own economies are stretched.

The amount in any deal reached at COP negotiations — often considered a “core” — will then be mobilized or leveraged for greater climate spending. But much of that means loans for countries drowning in debt.

But that meant little to vulnerable nations, many already battered by extreme weather made worse largely by emissions from the burning of fossil fuels they've had little to do with. Most of those emissions have come from the developed world since the Industrial Revolution.

“Our expectations were low, but this is a slap in the face,” said Mohamed Adow, from Power Shift Africa. “No developing country will fall for this. They have angered and offended the developing world.”

Nikki Reisch, director of the climate and energy program at the Center for International Environmental Law, said the offering was unacceptable not just because the money is low, but because “it’s really designed to escape and evade the legal obligation that developed countries have” to pay for the climate change they have largely caused.