WASHINGTON — After hinting that Hillary Clinton might be impeached if she is elected president, U.S. Rep. Michael McCaul stepped up his criticism Thursday, explicitly accusing Clinton of committing treason.

McCaul, an Austin Republican who chairs the House Homeland Security Committee, told the hosts of Fox and Friends on Fox News that Clinton's decision to host her emails on a private server during her tenure as secretary of state had endangered the country.

“She exposed [information] to our enemies,” McCaul said. “That not only jeopardizes her, and national security at home, but the men and women serving overseas.”

He added: “In my opinion, quite frankly, it’s treason.”

McCaul, who has worked hard to raise his profile in recent years, serves on GOP presidential nominee Donald Trump's national security advisory council. On Wednesday, he hinted there was a strong possibility that Clinton could be impeached if she were elected.

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If Clinton wins Tuesday, McCaul told Fox News, “and it looks like an indictment is pending, at that point in time under the Constitution, the House of Representatives would engage in an impeachment trial.”

Many Republicans in Texas believe McCaul may be laying the groundwork for a Senate run. He has made little effort to quell rumors that he might challenge GOP Sen. Ted Cruz for the seat in 2018. Ramping up the anti-Clinton rhetoric would raise his profile for a statewide race and appeal to the hard-core conservatives who propelled Cruz into the Senate.

"Never say never," McCaul told reporters in August.

The Clinton campaign declined to comment on McCaul's accusations, although Clinton has previously expressed regret for using a private server.