Donald Trump has told Fox that he made the decision to launch last week's missile strike on a Syrian airbase while he ate "the most beautiful piece of chocolate cake" with China's president.

The US leader made the revelation during a jocular interview with the Fox Business Network , and added that he informed Xi Jinping of the call while the pair finished the delicious dessert.

"I was sitting at the table we had finished dinner, we're now having dessert," Trump said, after agreeing to spill the beans because Fox had treated him "so good for for long".

"And we had the most beautiful piece of chocolate cake that you've ever seen and President Xi was enjoying it, and I was given the message from the generals that the ships are locked and loaded, 'what do you do?'

"And we made a determination to do it, so the missiles were on the way. And I said Mr President, let me explain something to you – this is during dessert – we've just fired 59 missiles – all of which hit by the way, unbelievable from, you know, hundreds of miles away, all of which hit, it's so incredible, it's brilliant, it's genius," he said.

"So what happened is," Trump said, returning from his tangent. "I said, 'we've just launched 59 missiles heading to Iraq – "

(AAP)

"Headed to Syria," the reporter corrected him.

"Yes, heading toward Syria," Trump said. "'And I want you to know that.' Because I didn't want him to go home, we were almost finished, it was a full day in Palm Beach, we're almost finished, what does he do, finish his dessert and go home and they say 'you know the guy you just had dinner with just attacked a country'."