BP is in talks with India's Reliance Industries and Essar Group to sell its African retail assets that could be worth as much as $500 million, four sources with direct knowledge of the matter told Reuters on Wednesday. It was not immediately known whether BP was showing the African assets to other potential buyers.

BP plans to sell $30 billion of assets over the next 18 months to cover costs related to the worst oil spill in U.S. history.

Reliance Industries, India's largest listed conglomerate, declined to comment, while a spokesman for steel-to-shipping conglomerate Essar said the company doesn't comment on speculation.

BP intends to sell its marketing business in Namibia, Malawi, Tanzania and Botswana and focus on South Africa and Mozambique.