Donald Trump has called out London's new Mayor Sadiq Khan for comments he made last week and challenged him to an IQ test.
The US presidential candidate appeared on Good Morning Britain in an interview with Piers Morgan when he accused Mr Khan of making "very rude" and "nasty" statements about the presidential hopeful, stating that he "will remember" the remarks.
The billionaire slammed the Mayor's claims that he has "ignorant views about Islam" and that Mr Trump shouldn't allow the mayor to be an "exception" in his ban on Muslims entering the US if he became president.
The comments by Mr Khan were made during a video interview with Reuters news agency last Tuesday (May 10).
David Cameron has called Mr Trump's plan for a temporary Muslim ban "stupid, divisive and wrong".
When asked about his remarks on the ban, he said: "I'm not the president, everything is a suggestion but we have a tremendous problem with radical Islamic terror."
But, on the finer point of the statement Mr Khan made last week, he added: "He doesn't know me, hasn't met me, doesn't know what I'm on about.
"I think they were very rude statements and frankly tell him I will remember those statements.
"When he won I wished him well. Now, I don't care about him, I mean it doesn't mean any difference to me.
"Let's see how he does, let's see if he's a good Mayor."