(Bloomberg) -- The COP29 UN climate summit released a first draft deal Thursday which puts at least $1 trillion of financing on the table, yet key details on where that money will come from still need to be ironed out.

Most Read from Bloomberg

• Paris to Replace Parking Spaces With Trees

• Trump Promises Could Have Seismic Impact on Washington Economy

• Tokyo’s Scorching Summers Focus Public Anger Against Tree Cutting

• New York’s Transit Agency Approves $9 Congestion Toll

• NYC Mayor Adams Names Jessica Tisch to Lead Police Head Amid Probes

Host Azerbaijan presented the 10-page draft finance deal shortly before 8 a.m. local time. It sparked heated debate among conference delegates in Baku about the lack of detail on how that level of funding can be achieved, including how much would come from loans that can put pressure on debt-laden poor nations.

The draft plan appeared to set a funding floor of $1 trillion a year coming from a range of sources that go beyond those included in an existing $100 billion target that expires next year. It included two options on how to get to that goal — one that gives countries time to ramp up to the increased sum and the other that seeks that sum annually from 2025 to 2035. Both would open the door for wealthy nations that aren’t currently donors, such as China and Saudi Arabia, to offer support.

In one option, “developing country parties willing to contribute to the support” would be invited to provide that help voluntarily, without it being counted toward the annual pledge. A second option makes clear that developed countries take the lead in pursuing the new finance goal, including “efforts of other countries with the economic capacity to contribute.”

Yet many key numbers were left blank and will form one of the battle grounds over the next days. Thorny questions over the scale of the finance — including how much would come in the form of affordable support, with grants or deeply discounted loans — were left unresolved.

“The lack of a clear bridging proposal and any numbers leaves negotiators with a huge amount of progress to make over the next day or two,” said Rob Moore, associate director at E3G.

Developed country negotiators, including those from the European Union and the US, have said any deal needs to be balanced between finance and securing emissions-cutting ambition.

A key element at this year’s climate summit has been to reaffirm a pledge made last year at COP28 in Dubai to transition away from fossil fuels. That objective features in just one of four possible options in a separate document under the implementation of the so-called Global Stocktake, which aims to get countries to bridge the big gap between climate targets and current actions toward them.