NEW YORK/BUENOS AIRES, Aug 1 (Reuters) – Argentina’s default this week did not “extinguish or reduce” the South American country’s debt obligations, a U.S. judge said on Friday, and he ordered negotiations between the country and holdout investors to continue. In a stern tone, U.S. District Judge Thomas Griesa in New York criticized the decision by Latin America’s No. 3 economy to default on $29 billion in debt earlier in the week rather than pay the holdouts as ordered.