US President Donald Trump said he has heard “interesting” things about Roswell, the crash site of an alleged UFO.

Mr Trump made the comments in an interview with his son, who asked if the White House incumbent could “let us know what’s really going on”.

“I won’t talk to you about what I know about it, but it’s very interesting,” he replied.

The Father’s Day-themed interview was hosted by the president’s reelection campaign.

In 1947, a rancher discovered unidentifiable debris in his sheep pasture outside Roswell in New Mexico.

Air Force officials said it was a crashed weather balloon, but sceptics questioned whether it was in fact at extraterrestrial flying saucer.

Decades later the US military acknowledged the debris was related to a top-secret atomic project and the UFO theory has flourished.

The president in the past has spoken sceptically about the possibility that there is something out there.

Tiger King
The president was also asked about Netflix hit Tiger King (Netflix/PA)

After his father offered that he heard some “interesting” things about Roswell, Mr Trump Jr asked the president might declassify that information someday.

“Well, I’ll have to think about that one,” the president responded.

Mr Trump also said that he had watched “a couple” of episodes of Netflix show Tiger King.

Joseph Maldonado-Passage, known as Joe Exotic, the star of the popular docu-series, is serving a 22-year prison sentence after he was convicted for hiring a hit man to murder a rival.

Mr Trump said during a press briefing in April that he was unfamiliar with Tiger King, after his son jokingly said on a radio show that he was lobbying the president for a pardon for Exotic.

The president on Thursday did not say when he was considering a pardon but sounded intrigued by the star of the show.

“That’s a whole strange deal going on,” Mr Trump said.

“I’ll tell you that’s a strange guy and a lot of strange people surrounding him.”