(Bloomberg) -- The US asked the Democratic Republic of Congo President Felix Tshisekedi to halt bidding on oil blocks in sensitive forests and peatlands in the Congo Basin to protect one of the world’s most important carbon sinks.

Tshisekedi has been defiant about Congo’s right to develop its hydrocarbons industry amid a controversial bidding round for 30 oil and gas blocks, some of which overlap with critical ecosystems. The US and Congo are creating a working group to discuss the protection of the central African nation’s peatlands and forests.

“We have asked that they withdraw some tracts to protect the forest,” US special presidential envoy for climate John Kerry told reporters Tuesday in the capital, Kinshasa, in a mixture of French and English. “We are very, very convinced that you will have adequate space for development, creation of jobs, sustainable use, but at the same time protecting the most sensitive areas of the basin, which are really an important asset for everybody in the world.”

Kerry is in Congo for preparatory meetings with environment ministers before the COP27 climate talks, which take place in Egypt next month.

Congo has the largest tropical peatlands and is home to most of the world’s second-biggest tropical rainforest after the Amazon. The Congo Basin’s peatlands alone contain about 29 billion tons of carbon, equivalent to about three years of worldwide carbon-dioxide emissions.

Read: Congo Peatlands, Which Slow Climate Change, Bigger Than Thought

African nations will be a particular focus of a Biden administration plan for $3 billion in annual funding for developing countries to adapt and manage the impacts of climate change, Kerry said. Congress is currently considering the proposal.

The administration is also trying to create a finance mechanism to unlock the “trillions of dollars” needed for the transition to the new energy economy, Kerry said.

“We’re looking at all aspects of finance, and de-risking is one of the things that’s been on the table for a while. Concessionary funding. Blended finance. There are a lot of terms that have been thrown around,” he said. “What we need to do is to define them now and pick a road to be able to accelerate the finance.”

Read: Kerry Woos Wall Street in Bid to Bolster US Climate Finance

Despite being one of the world’s poorest nations, Congo has major deposits of minerals key to the green energy transition, including lithium, copper and the largest reserves of battery mineral cobalt. A significant portion of its mineral trade is controlled by Chinese companies including CMOC Group Ltd. and Zijin Mining Group Co., though Kerry said he understood there was an unnamed cobalt mine up for sale.

“I know that the US is interested in being involved in securing some future prospects, but that’s not what the engagement is about,” Kerry said. “Our priority is the Congo Basin, not the cobalt. Not the mining.”

(Updates with Kerry comments on financing and cobalt from sixth paragraph.)

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