Democratic presidential hopeful Bernie SandersBernard (Bernie) SandersDems ponder gender politics of 2020 nominee 2020 Dem contenders travel to key primary states After Florida school shooting, vows for change but no clear path forward MORE criticized the Clinton Foundation for accepting donations from foreign governments in an interview aired Sunday, calling it a conflict of interest. 

"Do I have a problem when a sitting secretary of State and a foundation run by her husband collects many, many dollars from foreign governments — governments which are dictatorships?

"Yeah, I do have a problem with that. Yeah, I do," Sanders said on CNN's "State of the Union." 

When host Jake Tapper asked if he thought it was a conflict of interest, Sanders said, "I do."

Sanders and Democratic presidential front-runner Hillary ClintonHillary Diane Rodham ClintonWoman behind pro-Trump Facebook page denies being influenced by Russians Trump: CNN, MSNBC 'got scammed' into covering Russian-organized rally Pennsylvania Democrats set to win big with new district map MORE, a former secretary of State and the wife to former President Bill ClintonWilliam (Bill) Jefferson ClintonShould the Rob Porter outcome set the standard? Make the compromise: Ending chain migration is a small price to legalize Dreamers Assessing Trump's impeachment odds through a historic lens MORE, are locked in a tight battle ahead of Tuesday's presidential primaries.

The Clinton Foundation, a nonprofit established by Bill Clinton to implement development programs in third-world countries, has received donations from countries including Saudi Arabia. The kingdom gave between $10 million and $25 million to the foundation between the time the foundation was created through 2014, according to Politifact, though it stopped giving when she was secretary of State.