Donald Trump suffered a major slip of the lip during his economic speech in Detroit after he mispronounced "cities" as "titties". The billionaire businessman made the error as he unveiled his economic plan for the nation.

He promised to cut regulations and lower business taxes. He also vowed: "Our lower business tax will also end job-killing corporate inversions and cause trillions in new dollars to come pouring into our country," he said. "And, by the way, into titties like right here in Detroit."

Slight hesitation. Polite applause.

Trump appeared to be completely unaware he had made the mistake. His campaign is yet to respond.

The Twittersphere erupted with a mixture of delight and disbelief. "Look, the man said titties. There's no way around it," Buzzfeed Politics' Andrew Kaczynski posted.

Another Twitter user said: "#ManyPeopleAreSaying Trump is actually a stack of babies in a suit. This would explain his tiny hands and desire to talk about titties."