(IDEX Online) - Diamond billionaire Dan Gertler has lost two contracts to explore for oil in Democratic Republic of Congo (DRC).The move was announced by the government's hydrocarbons ministry, which said it was terminating production sharing agreements with two of his companies, Caprikat Ltd. and Foxwhelp Ltd.It is now reported to be considering possible sales of the blocks, along the country's border with Uganda, to oil companies Total or Tullow Oil instead. Proper exploration has long been delayed legal and political wrangling.The anti-corruption group Congo is Not for Sale claimed the oil rights "had been granted???,? ? in an opaque manner to companies affiliated to Dan Gertler".The group also claimed, in May, that DRC, one of the world's poorest nations, stood to lose at least $3.71bn from "suspect mining and oil deals" with Gertler.Gertler (pictured), an Israeli citizen, is subject to US sanctions - recently re-imposed by President Joe Biden - over allegations about his business activities in DRC.He began trading diamonds in the late 1990s when the country was in the middle of a bloody civil war and enjoyed a close friendship with the then-president Joseph Kabila. He has repeatedly denied allegations of wrongdoing.