Mitt Romney to release tax returns Tuesday WASHINGTON (Reuters) - Mitt Romney said on Sunday he will release tax returns for the last two years this week and admitted the flap over his returns hurt him in South Carolina, where he lost a primary to Newt Gingrich. "I will release my tax returns for 2010, which is the last returns which were completed, on Tuesday of this week," Romney said on Fox News Sunday. And I will also release at the same time an estimate for 2011 tax returns. "We made a mistake holding off as long as we did and it just was a distraction," the former Massachusetts governor added. Gingrich won 40 percent of the vote in the South Carolina primary on Saturday, while Romney came in a distant second with 28 percent. Romney, one of the wealthiest U.S. presidential candidates in history, emphasized he was releasing two years of returns after Gingrich posted his returns for only 2010 on Thursday. Gingrich and other Republican rivals attacked Romney in debates last week, asking why the former private equity executive would not release his returns. Romney had said he would release them in April and also paved the way for the disclosure by saying he paid a tax rate of around 15 percent, below many American wage earners, but in line with wealthy individuals who earn income from investments. Romney said his returns will be posted on his website. Reporting By Mary Milliken; Editing by Philip Barbara