Hillary Clinton's vice presidential running mate on Saturday chided Donald Trump for refusing to release his tax returns, noting that even former President Richard Nixon made his records public.

Sen. Tim Kaine, D-Va., made the comments to supporters in Manchester, N.H., Saturday afternoon, calling Trump's refusal to release his returns "a big deal."

"Now he was not known for the most elevated ethical standards," Kaine said to laughs, "but even Richard Nixon released his tax returns to the public when he was running for president, because he said […] 'The American public has a right to see my tax returns. They should see what my financial status is, they should see who I have connections with, they should see if I'm paying the taxes that support our veterans, that support our military, that support our social services.'"

Every Republican nominee in the past nine presidential elections has released his tax returns: Ronald Reagan (1980, 1984), George H. W. Bush (1988, 1992), Bob Dole (1996), George W. Bush (2000, 2004), John McCain (2008) and Mitt Romney (2012).

This year's GOP nominee has refused to release his tax returns thus far, citing an IRS audit. His running mate, Indiana Gov. Mike Pence, has not released his either.

On Friday, Clinton and Kaine both released their tax returns.