Secretary of State Rex Tillerson Rex Wayne TillersonGary Cohn: 'I haven't made up my mind' on vote for president in November Kushner says 'Alice in Wonderland' describes Trump presidency: Woodward book Conspicuous by their absence from the Republican Convention MORE reportedly clashed with White House officials over several issues in the past few weeks, including unreturned phone calls.

The Washington Post reported that Tillerson and his aides had conflicts with White House officials over Tillerson's habit of "neglecting to return phone calls," according to White House sources.

White House officials and the secretary of State were also at odds over larger issues, such as the administration's direction in Afghanistan, according to the Post.

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Tillerson on Wednesday pushed back on what he called an "erroneous" NBC News report and denied he has ever considered resigning from his post.

He refused, however, to directly answer a question regarding a claim that he called Trump a "moron" after a tense meeting with national security officials over the summer.

The State Department later Wednesday strongly denied Tillerson had called Trump a moron, saying the former Exxon Mobil chief executive doesn't "use that type of language."

Trump also pushed back against the NBC report, blasting the network as a "disgrace to good reporting" and calling for an apology to America.