Negotiators from small island states and the least-developed nations have walked out of negotiations during overtime United Nations climate talks, saying their climate finance interests were being ignored.

Nerves frayed on Saturday as negotiators from rich and poor nations huddled in a room at COP29 in Baku, Azerbaijan to try to hash out an elusive deal on finance for developing countries to curb and adapt to climate change.

But the rough draft of a new proposal was soundly rejected, especially by African nations and small island states, according to messages relayed from inside.

“We’ve just walked out. We came here to this COP for a fair deal. We feel that we haven’t been heard,” said Cedric Schuster, the Samoan chairman of the Alliance of Small Island States, a coalition of nations threatened by rising seas.

“[The] current deal is unacceptable for us. We need to speak to other developing countries and decide what to do,” Evans Njewa, chair of the Least Developed Countries (LDC) group, said.

When asked if the walkout was a protest, Colombia Environment Minister Susana Mohamed told The Associated Press news agency: “I would call this dissatisfaction, [we are] highly dissatisfied.”

With tensions high, climate activists also heckled United States climate envoy John Podesta as he left the meeting room.

They accused the US of not paying its fair share and having “a legacy of burning up the planet”.

Developing countries have accused the rich of trying to get their way – and a smaller financial aid package – via a war of attrition. And small island nations, particularly vulnerable to climate change’s worsening effects, accused the host country presidency of ignoring them throughout the talks.

Panama’s chief negotiator Juan Carlos Monterrey Gomez said he has had enough.

“Every minute that passes, we are going to just keep getting weaker and weaker and weaker. They don’t have that issue. They have massive delegations,” Gomez said.

“This is what they always do. They break us at the last minute. You know, they push it and push it and push it until our negotiators leave. Until we’re tired, until we’re delusional from not eating, from not sleeping.”

The last official draft on Friday pledged $250bn annually by 2035, more than double the previous goal of $100bn set 15 years ago, but far short of the annual $1 trillion-plus that experts say is needed.

Developing nations are seeking $1.3 trillion to help adapt to droughts, floods, rising seas and extreme heat, pay for losses and damage caused by extreme weather, and transition their energy systems away from planet-warming fossil fuels and towards clean energy.

Wealthy nations are obligated to pay vulnerable countries under an agreement reached at COP talks in Paris in 2015.

Nazanine Moshiri, senior climate and environment analyst at the International Crisis Group, told Al Jazeera that rich countries were being restricted by economic conditions.

“Wealthy nations are constrained by tight domestic budgets, by the Gaza war, by Ukraine and also other conflicts, for example in Sudan, and [other] economic issues,” she said.

“This is at odds with what developing countries are grappling with: the mounting costs of storms, floods and droughts, which are being fuelled by climate change.”

Teresa Anderson, the global lead on climate justice at Action Aid, said, to get a deal, “the presidency has to put something far better on the table”.

“The US in particular, and rich countries, need to do far more to show that they’re willing for real money to come forward,” she told the AP. “And if they don’t, then LDCs are unlikely to find that there’s anything here for them.”

Despite the fractures between nations, some still held out hopes for the talks. “We remain optimistic,” said Nabeel Munir of Pakistan, who chairs one of the talks’ standing negotiating committees.

Panama’s Monterrey Gomez highlighted that there needs to be a deal.

“If we don’t get a deal I think it will be a fatal wound to this process, to the planet, to people,” he said.