Donald Trump has weighed in on Britain's reported rise in crime, linking it to "radical Islamic terror" in a tweet and saying "not good, we must keep America safe!"

"Just out report: "United Kingdom crime rises 13 per cent annually amid spread of Radical Islamic terror." Not good, we must keep America safe!" the US President tweeted on Friday morning.

The comment came after official figures released on Friday showed a 13 per cent increase in violent crime in England and Wales - with a total of 5.2 million offences in the year to the end of June.

The figures have mostly been attributed to an increase in sex and knife crimes.