STERLING, Va. — The strained relationship between President Trump and Secretary of State Rex Tillerson came under renewed focus Sunday, as the nation’s top diplomat insisted that Trump has not undermined him even as he again refused to deny calling the president ‘‘a moron.’’
Tensions between the two men have grown while the nation faces a series of high-stakes international crises, including the threat posed by North Korea and fate of the Iran nuclear deal, and threatens to sow doubt about American allies as to whether Tillerson can speak authoritatively for the United States.
The secretary of state insisted that he has a strong working relationship with the president without any name-calling.
‘‘I call the president ‘Mr. President.’ He and I have a very, very open, frank, and candid relationship. We have a very open exchange of views on policy,’’ Tillerson said during an interview on CNN’s ‘‘State of the Union.’’
‘’At the end of the day, he makes decisions,’’ Tillerson said. “I go out and do the best I can to execute those decisions successfully.
‘‘He has assembled a very, I think, unconventional team,’’ Tillerson continued. ‘‘He himself is an unconventional president. He’s assembled an unconventional Cabinet. I’m an unconventional pick for secretary of state.’’
But Tillerson would not answer repeated questions as to whether he called Trump, as has been reported, ‘‘a moron’’ after a tense meeting at the Pentagon in July during which the national security team stressed to a skeptical president the need for a robust American presence around the globe.
Tillerson parried: ‘‘I’m not going to deal with that kind of petty stuff,’’ he said.
The firestorm around the ‘‘moron’’ comment, which was first reported by NBC, prompted Tillerson to hold a remarkable press conference at the State Department earlier this month during which he pledged fealty to Trump but did not deny using the word.
A State Department spokeswoman later denied that Tillerson said it.
But the reports infuriated Trump, who privately bashed his secretary of state to associates and publicly challenged Tillerson to an IQ test.
‘‘And I can tell you who is going to win,’’ Trump told Forbes magazine. The White House later said he was joking.
But despite Tillerson’s efforts to move beyond the story, it has created a perception among many in Washington that the clash with Trump has weakened the secretary of state’s voice on the world stage.
Senator Bob Corker, a Tennessee Republican who has recently become a vocal critic of the president, last week suggested that Tillerson had been ‘‘castrated’’ by the president.
Tillerson, a ranch owner, joked that he had not been gelded.
The White House did not immediately respond to Tillerson’s interview. Trump visited his Virginia golf course on Sunday.
People close to Trump say the president has grown increasingly dissatisfied with the former Exxon CEO, whom he views as holding a conventional view of America’s role in the world and lacking star power.
Tillerson, meanwhile, is said to have grown weary of Trump’s contradicting his pronouncements and of becoming increasingly isolated in a capital to which he has never warmed.
Trump himself has been irked by Tillerson’s advocacy of staying in both the Paris climate deal and the Iran nuclear pact, and has complained to associates that he does not like how Tillerson candidly voices his disapproval to the president in meetings, according to White House officials and outside advisers.
The men also disagreed on the nation’s Afghanistan strategy.
In a separate development, Trump’s reelection committee paid almost $238,000 in the third quarter to the law firm representing Donald Trump Jr. in connection with ongoing investigations of Russian interference in the 2016 election, Bloomberg News reported, citing campaign finance disclosures.