DOHA, Qatar -- Leaders of countries vulnerable to climate change say their nations have not benefited from $30 billion in global warming aid over the past three years.

Diplomats gathering here for U.N. climate change negotiations are demanding the wealthy countries that put up the money be more transparent about exactly where the funding comes from and where it is going.

They are calling for $60 billion over the next three years as nations try to hit a target of $100 billion annually in public and private aid by 2020, a portion of which will flow through a new Green Climate fund.

"We want an incremental increase of accumulation of the fund," said Bangladesh Environment Minister Hasan Mahmud.

Of the $30 billion in so-called fast-start funding that wealthy countries maintain they have delivered, Mahmud said, "On the ground, we see less than $4 billion. There is big ambiguity. There is a demand, a question to resolve. How much really they have disbursed? They have to make it clear. That is our demand."

Rhoda Peace Tumusiime, commissioner for rural economy and agriculture at the African Union, said African nations are slowly seeing climate aid "trickling in" but also said the funding needs to be more transparent.

"Where we see dollars being available, it is part of the old development assistance just being shifted," she said. "We in Africa, this is what we are worried about."

The fight is expected to come to a head as ministers arrive today for the high-level segment of negotiations.

Donor nations claim to meet their targets

Officials here with the United States, the European Union and other industrialized nations say they have met and even exceeded their funding commitments and insist that their governments will continue to make dollars for climate aid a priority.

State Department Special Envoy for Climate Change Todd Stern yesterday said nations have collectively put forward $33.6 billion with about $7.5 billion from the United States -- a figure he called "quite good."

"This is for us, for Europe, for many players, obviously very challenging fiscal times. And we have every intention to continue to pressing forward with funding of that same kind of level, to the greatest extent that we can," Stern said.

"Obviously we need to get money, to appropriate from Congress ... but I expect that to continue. We're committed to it, and we're committed to the longer-term goal of mobilizing funding by 2020 in the context of the right kind of mitigation and transparency."

But wealthy nations maintain that Doha is not the place to discuss new financial commitments. Many say they want to see how the burgeoning Green Climate Fund is designed before pledging funds.

The battle for money is expected to be a bruising one over the coming days. Already, according to activists, it has led to negotiators' issuing a blank page of text under the heading "finance" in draft negotiations to symbolize perceived inaction from developed nations.

"The empty white page matches the climate finance pledges of developed countries under the U.N. climate convention. Empty in 2013. A big zero," said Chee Yoke Ling, director of the Third World Network, a Malaysian based nongovernmental organization providing detailed analysis of the talks.

Said Brandon Wu, a climate campaigner at ActionAid, "Those broken promises threaten to break the talks. If the U.S. and others continue to refuse an agreement on new levels, on transparency and on sources, then developing countries should consider walking away from the table completely."