A senior House Republican warned Friday that even Republicans in Congress wouldn't look too kindly on a decision by President Trump to fire Special Counsel Robert Mueller.

"I think if he fired Bob Mueller, I think he would see a tremendous backlash from both Democrats, but also House Republicans," Rep. Michael McCaul, R-Texas, who chairs the House Homeland Security Committee, said on MSNBC.

Trump hinted Wednesday that he may be considering such a move, saying that "a special counsel should never have been appointed" and that Mueller, in particular, has "conflicts." He also discouraged investigators probing his personal finances, a warning that coincided with reports that Mueller's team is reviewing at least some business transactions.

McCaul argued that Trump should focus on advancing a political message.

"We want, again, a more disciplined White House on message so we can stay on message and get done the things we need to get done," he said amid news that Trump press secretary Sean Spicer had resigned. "I just reauthorized the department of Homeland Security for the first time since it was created 15 years ago on the floor yesterday, but that's not what we're talking about. We're talking about this disarray in the White House. And so, it is frustrating. I hope with a new team, with new people around him, perhaps he can get back on message."

Trump discussed the Russia investigation in a wide-ranging interview with the New York Times that was published Wednesday. "If Mueller was looking at your finances and your family finances, unrelated to Russia ? is that a red line?" a reporter asked.

The president replied "yes," although he declined to say if he would enforce the line by firing Mueller. "I think that's a violation," Trump said. "Look, this is about Russia. So I think if he wants to go, my finances are extremely good, my company is an unbelievably successful company ... But I have no income from Russia."