Virginia Sen. Tim Kaine defended the Obama administration on Sunday amid new questions about a $400 million cash payment to Iran and whether it was ransom for the return of four American hostages.

"There was a legitimate claim against the United States. The United States bargained it down to a fraction. We're making claims in international tribunals, and we're having claims made against us all the time," the Democratic vice presidential candidate told NBC News.

President Obama has pushed back on allegations that the cash delivered to Iran in January was a ransom payment. The payment was first reported by the Wall Street Journal last week and described as the initial installment in a $1.7 billion settlement reached between the two countries as part of the Iranian nuclear deal.

Republicans, including Donald Trump and Mike Pence, have claimed the timing of the payment raises suspicions and that the money could be going directly toward terrorist groups in the region.

"We bargain it down to a fraction and paid a portion of the claim, and we got hostages home. Both of those things are appropriate," Kaine said.

The Virginia senator also defended Clinton's recent claims about her private email practices.

"She said it was a mistake," Kaine told NBC. "I am not presumptuous enough to start thinking about how I'm going to do things after November. But I know that this is something that she's learned from, and we're going to be real transparent, absolutely."