[VOA] Gaborone, Botswana -- Botswana's president, Mokgweetsi Masisi, is threatening to walk away from a diamond mining deal with industry giant De Beers unless the firm offers better terms. Under the current deal, which expires in June, Botswana - Africa's largest diamond producer - is entitled to purchase up to 25% of the stones mined in a joint venture. Analysts say Botswana is in a strong position to push for a 50-50 arrangement.