WASHINGTON (Reuters) - U.S. President Donald Trump denied on Thursday that Rex Tillerson had threatened to resign after a news report that the secretary of state had called him a moron and had to be repeatedly persuaded not to leave the administration. “Rex Tillerson never threatened to resign,” Trump said in his most direct refutation of the resignation report. “This is Fake News put out by @NBCNews. Low news and reporting standards. No verification from me.”   On Wednesday, the top U.S. diplomat, whose tenure has been dogged with rumors about unhappiness with Trump’s policies and rhetoric, said he was committed to the president’s agenda and had never considered resigning. NBC reported that, in a session with Trump’s national security team and Cabinet officials at the Pentagon, Tillerson had openly criticized the president and referred to him as a moron, citing three unidentified officials familiar with the incident. Tillerson sidestepped the issue when taking questions after making a televised statement to the media. Trump adviser Kellyanne Conway also tried to tamp down speculation that Tillerson was on the verge of leaving the administration.  “He said he has never once thought of resigning,” Conway said on CNN. “We’re glad he’s the secretary of state.”  Another Cabinet member, Health and Human Services Secretary Tom Price, announced his resignation last week after acknowledging he used taxpayer funds to travel on private planes. 