Donald Trump confessed what he really thinks about the Secret Service in an interview after they put his life at risk - and disclosed another glaring oversight. 

The Republican presidential candidate revealed he was not warned about his attacker by the Secret Service - despite agents receiving worrying reports from rally-goers before Trump even got on stage. 

In an interview with Fox News host Jesse Watters, the former president discussed his ill-fated rally in Butler, Pennsylvania. 

Trump told the interviewer that 'nobody mentioned' Thomas Matthew Crooks, the 20-year-old gunman, despite the fact that he was being monitored for 'an hour' before the shooting. 

'Mistakes were made,' Watters told Trump. 'They were monitoring this guy for an hour beforehand. No one told you not to take the stage?'

'Nobody mentioned it,' the former president replied. 'Nobody said it was a problem.'

'[They] could've said, "Let's wait for 15, 20 minutes, 5 minutes." Nobody said…I think that was a mistake,' he added.

Trump, along with the rest of the United States, later questioned how Crooks could have possibly made it onto the roof to begin with. 

'How did somebody get on that roof?' Trump questioned. 'And why wasn't he reported, because people saw he was on that roof.'

Trump revealed that security agents were alerted that someone was on the roof with a gun before he even walked out on stage - and did not stop him from doing so. 

'When you have Trumpers screaming, the woman in the red shirt, 'There's a man on the roof,' and other people, 'There's a man on the roof and who's got a gun,'…that was quite a bit before I walked on the stage. And I would've thought someone would've done something about it,' Trump said.