WASHINGTON — The friend of Donald Trump who claimed the president is thinking about firing Robert Mueller, the special counsel in the Russia investigation, slammed the White House on Tuesday for the way it handled his politically explosive remark.

Chris Ruddy, the chief executive of Newsmax Media and a longtime confidant of Trump, said it was "amateur hour" at the White House and blasted press secretary Sean Spicer.

"Spicer issued a bizarre late-night press release that a) doesn't deny my claim the President is considering firing Mueller and b) says I didn't speak to the President about the matter — when I never claimed to have done so," Ruddy said in a statement to NBC News. "Memo to Sean: focus your efforts on exposing the flim-flam Russian allegations against POTUS and highlighting his remarkable achievements!"

Ruddy went on to say: "Don't waste your time trying to undermine one of your allies."

He told PBS's "NewsHour" on Monday that Trump was "considering, perhaps, terminating the special counsel." In a statement Monday evening, Spicer responded that Ruddy "never spoke to the president regarding this issue," adding that "only the president or his attorneys are authorized to comment" on the matter.

Related: Rumor That Trump May Fire Mueller Sets Washington Alight

Ruddy, for his part, did not claim he met with Trump during his visit to the West Wing on Monday. Sources familiar with his visit told NBC News he met with chief of staff Reince Priebus and chief strategist Steve Bannon.

Ruddy said he had a conversation with the president last week, but that Mueller did not come up.

Robert Mueller testifies during a hearing before the Senate Judiciary Committee June 19, 2013 on Capitol Hill in Washington, D.C. Alex Wong / Getty Images

He emphasized that he thinks removing Mueller would be a mistake, but he described the special counsel's power and his appointment to the role as "illegitimate."

"Do I think he will actually fire him? No," Ruddy told MSNBC's Kristen Welker on Tuesday afternoon. "But I do think it's an option, yes."

Testifying before a Senate Appropriations subcommittee Tuesday morning, Deputy Attorney General Rod Rosenstein said that he has hiring and firing authority over Mueller, whom he appointed, because Attorney General Jeff Sessions has recused himself from the Russian investigation. Asked if he had seen any evidence to suggest Mueller be fired, Rosenstein replied, "No, I have not.”

When asked what he would do if the president ordered him to fire Mueller, Rosenstein replied, “I’m not going to follow any orders unless I believe those are lawful and appropriate orders. Under the regulation, special counsel Mueller may be fired for only good cause, and I am required to put that cause in writing.”

Even before Ruddy's remarks Monday, other prominent Republicans had been questioning Mueller's mandate and his fitness to carry it out.

Related: What You Need to Know About Robert Mueller

In a panel discussion over the weekend on "Fox News Sunday," former House Speaker Newt Gingrich called Mueller's investigation "a witch hunt."

Gingrich struck a different chord in an interview with CBS' "This Morning" on Tuesday, flatly denying that Trump is considering firing Mueller. The former GOP presidential candidate claimed he "talked about this a little bit" with the president on Monday evening.

Peter Alexander reported from Washington, and Daniel Arkin from New York.