President Donald Trump remains concerned about a possible informant infiltrating his campaign, despite Republican House Oversight Committee Chairman Trey Gowdy comments that the FBI was appropriate to use the tactic, White House press secretary Sarah Huckabee Sanders said Wednesday.

"Clearly, there's still cause for concern that needs to be looked at," Sanders said at the daily briefing. "Let's not forget the deputy of the director of the FBI was fired for misconduct."

She was referring to Andrew McCabe, whom Attorney General Jeff Sessions fired in March for leaking information to the news media and not being candid with Justice Department investigators on the issue.

"The president's concerned about the matter — and we'll continue to follow the issue," Sanders said.

Gowdy, a four -term representative from South Carolina, told Fox News on Tuesday that the FBI was appropriate in using the informant.

"I am even more convinced that the FBI did exactly what my fellow citizens would want them to do when they got the information they got, and that it has nothing to do with Donald Trump," Gowdy told Martha MacCallum.

Gowdy drew his conclusions after a classified meeting last week with FBI Director Chris Wray and Deputy Attorney General Rod Rosenstein on the Russia investigation.

Trump has repeatedly slammed special counsel Robert Mueller's probe as a "witch hunt" and has accused the FBI of planting "spies" in his team during the presidential campaign.

Sanders re-emphasized McCabe's firing in reiterating Trump's call for further investigation of the FBI and Justice Department on Russia.

"The deputy director of the FBI was fired for misconduct," she said. "There are a number of things that have been reported on.

"That shows not just for the president, but a number of Americans, have a large cause for concern.

"We'd like to see this fully looked into — and we'll continue to follow that matter."