BP and Eni announced in May that they had entered into talks to merge their oil, gas and liquefied natural gas (LNG) operations in Angola to form one of Africa's largest energy companies.

Spinning off oil and gas assets is seen as a way for them to squeeze more out of such assets as they try to reduce their greenhouse gas emissions and shift towards renewable energy.

It is also seen as a way to remove debt from the parent company to the independent joint venture, making it easier for the parent companies to raise money for low-carbon businesses.

BP and Eni have in recent weeks contacted a number of leading Western banks to request proposals to raise $1.5-$2 billion for the joint venture, four sources said.

"They are trying to deconsolidate the Angolan assets and want to raise cash for the joint venture's upstream operations," one of the sources said.

"The idea is not just to cut debt but to invest more in Angola and faster," a second source said.

BP and Eni declined to comment.

Speaking to Reuters in September, BP CFO Murray Auchincloss said the joint venture aimed to create "a much more efficient company" to explore, drill and produce oil and gas in Angola.

However, many Western banks are unlikely to lend the money given growing investor and government pressure for them to reduce investments in fossil fuels, particularly in countries where environmental standards are not tightly monitored, the sources said.

On Friday, a senior U.S. climate envoy said that Western fossil fuel companies investing in Africa face a significant risk of regulatory action that is becoming increasingly explicit as the world tries to tackle dangerous climate change.

(Reporting by Ron BoussoAdditional reporting by Stephen Jewkes in MilanEditing by Kirsten Donovan and Frances Kerry)

By Ron Bousso and Stephen Jewkes