Vice President Joe Biden denounced Republican presidential challenger Mitt Romney on Tuesday as a candidate with something to hide.

Biden, campaigning for President Barack Obama in the battleground of Nevada, told Hispanic leaders that Romney doesn't live up to the openness that his father represented when he ran for president 44 years ago. The vice president said Romney's father, George Romney, released 12 years of tax returns when he unsuccessfully sought the Republican nomination in 1968.

In a speech to the annual conference of the National Council of La Raza, Biden accused Romney of releasing only one year of his tax returns, "making a lie of the old adage: Like father, like son."

Romney has released his 2010 tax return and an estimate for 2011.

Biden said Romney's father "released 12 years of tax returns because, as he said, 'One year could be a fluke, perhaps done for show.'"

Biden added, to applause from the audience, that Romney "wants you to show your papers, but he won't show us his!"