The Democratic Party’s effort to overturn President Donald Trump’s election results has been stymied by evidence of widespread fraud, according to a new report from the nonpartisan Congressional Research Service.

The report found that in 2016, more than 5 million provisional ballots were cast during the early stages of the election process, an unprecedented number.

The Democratic Congressional Campaign Committee (DCCC) said it is investigating a pattern of voting irregularities.

The DCCC also said it will be “making changes to ensure voters have confidence in the outcome of the 2020 election.”

“The Democratic Party has been working to ensure that voters in 2018 will have the information they need to make an informed decision in the upcoming elections,” said DCCC spokeswoman Lauren Dillon in a statement.

“We are committed to doing everything we can to ensure this happens in 2020.”

The party has been criticized for a lack of transparency in the process of casting ballots.

The Republican National Committee said it would investigate the allegations and was working to “expose the fraud and corruption of the Trump/Pence machine.”