LUXEMBOURG (Dow Jones)--Europe's highest court Tuesday backed a decision by Europe's antitrust regulator that accepted a deal from diamond dealer De Beers SA to reduce the amount of rough diamonds it buys from Russian supplier Alrosa Co. The decision by the European Court of Justice overturns a lower court ruling that struck down the decision by the European Commission. "The Court of Justice set aside the judgment of the General Court and upheld the commission's decision making binding the commitments offered by De Beers to cease all purchases of rough diamonds from Alrosa," the court said in a statement. "In adopting the decision, the commission didn't make an error of law or a manifest error of assessment," it said. The De Beers Group controls some 70% of the world's rough diamond supplies, which it sells to manufacturers and dealers. The company, majority owned by Anglo American PLC (AAL.LN), is registered in Luxembourg but based in Johannesburg, South Africa. -By Mike Gordon, Dow Jones Newswires; +352 691 180 766; [email protected] (END) Dow Jones Newswires June 29, 2010 04:00 ET (08:00 GMT)