London Mayor Sadiq Khan is hitting back against President Donald Trump , who attacked the citys leader ahead of his U.K. visit with a series of insults sent over Twitter.

Thats the sort of behavior Id expect from my daughters when they were 11, Khan told Sky News on Tuesday. But look, its for him to choose how he decides to tweet.

As Trumps flight to Europe touched down on Monday, he fired off a duo of tweets trashing Khan as a terrible mayor and a stone cold loser . The trigger for the tirade was Khans Observer op-ed published Saturday in which he compared the president to the fascists of the 20th century , arguing that Britain should not greet him by rolling out the red carpet.

Khan also took several shots at Trumps divisive rhetoric and policies, arguing that he uses xenophobia, racism and otherness as an electoral tactic and lies deliberately and repeatedly to the public.

In response, Trump told Khan in his tweet that he was foolishly nasty to the visiting President of the United States, by far the most important ally of the United Kingdom.

In Khans Tuesday remarks, he made clear that he indeed views the U.S. as our closest allies.

We have a special relationship with them, he said. I compare it to having a best friend. Our expectations of our best friend our much higher than they are of an acquaintance or just a friend, and if weve got differences, we should be able to express them honestly and candidly.

Trump is wrapping up his three-day visit which has been met with thousands of demonstrators protesting his trip.

He claimed in a Tuesday press conference with Prime Minister Theresa May that reports of the protests were fake news, however, they could be heard during the briefing.