President-elect Donald Trump shakes hands with former Massachusetts Gov. Mitt Romney. Thomson Reuters Some of President-elect Donald Trump's most loyal allies publicly cautioned him this week against selecting Mitt Romney as secretary of state.

The allies — Sean Hannity, Newt Gingrich, and Mike Huckabee — all warned Trump about the possibility that Romney, the 2012 Republican presidential nominee, would not be loyal to him while serving in the nation's top diplomatic post.

Hannity, who seemingly supports former New York City Mayor Rudy Giuliani for the post, said on his Fox News program Tuesday night that he "cannot understand" why Trump would consider Romney in light of the criticism he unleashed on Trump during the campaign.

"The one speech in particular, it was brutal, eviscerating Donald Trump," Hannity said, referring to an anti-Trump speech Romney delivered during the primary season.

"Why would anybody think about bringing this guy in, and how would you ever expect him to be loyal in light of how he acted?" he added.

Gingrich agreed, suggesting on "Fox and Friends" on Wednesday that the former Massachusetts governor could go rogue if selected for the position.

"Gov. Romney wanted to be president, not secretary of state, and you have to ask the question: When he goes overseas is he going to be the secretary of state for President Trump, or is he going to be Mitt Romney's own secretary of state?" Gingrich said.

The former House speaker said "there are a lot of other people who are more qualified than Romney" who could serve as secretary of state. He hinted when talking with reporters at Trump Tower on Monday that he favors Giuliani over Romney for the position.

Huckabee took things a step further, saying on "Fox and Friends" on Wednesday that Romney should have to go "to a microphone in a very public place and repudiate everything he said" about Trump during the election season.

Otherwise, the former Arkansas governor said, "it would be a real insult to all those Donald Trump voters who worked really hard" and were loyal to him as a long-shot candidate.

Romney met with Trump last weekend to discuss a possible appointment as secretary of state. CNN reported Tuesday night that Romney was seriously considering serving in such a capacity.

Trump was also considering Giuliani for the position, but his nomination may face a more perilous road being confirmed by the Senate. Kentucky Sen. Rand Paul, a Republican, recently warned Trump against selecting him for the position.