Former House Speaker Newt Gingrich said Monday night President Trump would be making a "big mistake" if he fired Attorney General Jeff Sessions.

"There's a lot of good in Jeff Sessions," Gingrich said on Fox News. "I think it would be a big mistake for the president to do anything except move forward with him."

Gingrich, a former Republican lawmaker from Georgia who advised Trump during the campaign, said he would be "very surprised" if the president fired Sessions.

He cited Sessions' loyalty to Trump: Sessions was an early supporter in the campaign and the first GOP senator to endorse him.

"Sessions was the first senator to endorse Trump," Gingrich said. "Sessions stayed with Trump when he was 10 points behind during the whole taping of the conversation about sex and all that stuff. Jeff Sessions has been loyal all the way through."

Gingrich also credited Sessions for implementing strict immigration policies with the Justice Department.

"When you look at the work they are doing cooperating with Homeland Security, on rolling up MS-13 gangs all over America, you look at what Jeff is doing taking on sanctuary cities and the liberal mayors who refused to protect their citizens from criminals," Gingrich said.

Sessions is under increased scrutiny after Trump told The New York Times last week that he would not have chosen Sessions to be attorney general if he knew Sessions would recuse himself from the Russia investigation.

Trump also criticized Sessions for giving "bad answers" during his confirmation hearing about his Russia contacts.

On Monday, Trump piled on, referring to Sessions' status as "beleaguered" in a Twitter post.

Sessions has said he intends to remain attorney general.

Gingrich said if Trump fired Sessions, it would send a bad message to other leaders in the administration.

"I would just point out loyalty is a two-way street," Gingrich said. "There's a point here where people have to say the guy was with you from the very beginning and he makes one big mistake? You really dump him? And if you do, what signal do you send to everybody else on the team?"