UPDATE 3-Petrobras posts first loss in 13 years; results shock

RIO DE JANEIRO, Aug 3 (Reuters) - Brazil's state-led oil giant Petrobras on Friday posted its first quarterly loss in more than 13 years, fanning concerns that the company, hampered by government intervention and soaring costs, will fail to meet its goal of becoming one of the three biggest crude producers by the end of the decade.