LONDON — Private equity firm Kohlberg Kravis Roberts & Co. wants to buy the diamond mining operations of BHP Billiton and Rio Tinto and merge them to create a challenger to the two diamond industry leaders, De Beers and Alrosa, The (London) Sunday Times reported.

KKR is said to be leading the bidding for BHP’s Ekati diamond mine in Canada for around $750 million, the paper said without citing sources.

The private equity firm plans to combine Ekati with Rio Tinto’s $2 billion diamond mining business which is also up for sale, the paper said.

The combined businesses would control around 15 percent of world diamond supply, the report said.