Hillary Clinton's campaign released a new attack ad Friday highlighting Donald Trump's refusal to release his tax returns.

The ad, titled "Even Republicans," includes a collection of quotes from conservatives, including Sen. Ted Cruz, R-Texas, former Massachusetts Gov. Mitt Romney and political analyst George Will, who have suggested Trump refuses to release his returns because he has something to hide.

It's possible the returns will show Trump is not nearly as wealthy as he says he is, Romney suggested. Others have suggested the returns will show the GOP nominee hasn't donated nearly as much to charity as he claims.

The video also hits Trump over the fact that every candidate for president for the last 40 years has released his returns.

Clinton's campaign announced that she will soon release her 2015 tax returns. Her running mate, Sen. Tim Kaine, D-Va., is expected to release his returns for 2015, as well as his returns for the last 10 years.

The Democratic presidential candidate has already released her returns dating back to 2007–2014.