The Department of Homeland Security is investigating 1,620 cases of voter fraud involving noncitizens, DHS Secretary Markwayne Mullin said. 

Mullin told Fox News that the department has made 151 arrests and is investigating 300,000 additional cases, which are all based on a list compiled from states' voter rolls. 

"We're scrubbing them. We're comparing them to those that are in the country illegally, those that are legal permanent residents and those that are citizens" to determine if they voted legally, Mullin said in an interview with Fox contributor Kayleigh McEnany. 

Mullin said the investigation reveals that President Donald Trump was correct when he said there have been many cases of fraud in elections. 

"We continue to see that. Every single vote, Kayleigh, that we talk about, that was at the hands of an illegal canceled out a citizen that was legally registered and able to vote," Mullin said.