The president didn't mention that his White House like every previous administration has officials serve as unnamed sources frequently as a way of informing reporters of policy and operational matters. The media also uses anonymous sources to protect the identity of people who might fear retribution for sharing sensitive information.
Hours before the president spoke at the conservative conference, for instance, the White House invited reporters to a "background briefing" where it was insisted upon that the media not reveal the names of officials holding the information session.
His birther claims
Over several years, Trump used unidentified sources to claim that former President Obama was not born in the United States, which if true would have made him unqualified to be president.
Not until September 2016, after Trump became the Republican nominee for president, did he publicly acknowledge that Obama was born in the U.S.
Unsupported claims during the campaign
Another example of Trump's making a claim without specific sources came in November 2015, when he asserted that he saw "thousands" of people in the United States cheering the attacks on Sept. 11 that brought down the World Trade Center.
At a campaign event the day after the interview, he doubled down on that assertion.
"Lo and behold I start getting phone calls in my office by the hundreds, that they were there and they saw this take place on the internet," Trump said in Ohio.
ABC News checked a variety of footage from the time of the attacks and the weeks after, finding no basis for his claim.
"I mean, what was he doing — what was he doing with Lee Harvey Oswald shortly before the death? Before the shooting?" Trump said during an interview with Fox News. "It's horrible."
The Cruz campaign immediately denied the claims made by The Enquirer and criticized Trump for his remarks.
ABC News' Jon Karl and Serena Marshall contributed to this report.