U.S. Democratic presidential candidate Hillary Clinton addresses supporters at the Electric Park Ballroom in Waterloo, Iowa January 11, 2016. REUTERS/Aaron P. Bernstein

WASHINGTON (Reuters) - The FBI is widening its investigation of Democratic presidential candidate Hillary Clinton’s use of a private email account while she was U.S. secretary of state to determine whether any public corruption laws were violated, Fox News reported on Monday.

The Federal Bureau of Investigation has been looking into whether classified material was mishandled during Clinton’s tenure at the State Department from 2009-2013.

It will expand its probe by examining possible overlap of the Clinton Foundation charity with State Department business, Fox reported, citing three unidentified intelligence officials.

“The agents are investigating the possible intersection of Clinton Foundation donations, the dispensation of State Department contracts and whether regular processes were followed,” Fox quoted one of its unidentified sources as saying.

The FBI and the State Department had no immediate comment.

Clinton has said she used communication practices that were widespread across the government. She has said there has been no evidence that she broke the law.

In an interview with the Des Moines Register editorial board in Iowa, Clinton called the Fox report an “unsourced, irresponsible claim” with “no basis,” the newspaper’s political reporter, Jason Noble, said on Twitter.

Clinton, the front-runner to be the Democratic candidate in November’s presidential election, has been criticized for using the private email account hosted on a private computer while secretary of state.

Republican National Committee Chairman Reince Priebus issued a statement calling the Fox report “a very troubling development.”