Sadiq Khan did not meet with Mr Trump and made it very clear that he did not think that Trump should be welcomed in the United Kingdom - and even filmed a video saying that before the President's arrival.
Speaking in central London on Monday, Mr Khan said: "It's remarkable that you've got the president of the U.S. amplifying the tweets of a far-right activist, amplifying a racist tweet. Khan is a disaster - will only get worse!" he wrote.
Mr Javid said: "I think President Trump should stick to domestic policies and I think it is unbecoming of a leader of such a great state to keep trying to interfere in other countries' domestic policies".
"He is a national disgrace who is destroying the city of London", a follow-up message read.
Two teenagers were murdered within minutes of each other in different parts of the capital on Friday, while a man was stabbed to death on Saturday afternoon.
As with many of President Trump's arguments, this is a feud that has been going on for a couple of years.
But Labour Leader Jeremy Corbyn defended Mr Khan, saying: "Absolutely terrible to see Donald Trump using the tragedy of people being murdered to attack the Mayor".
On Katie Hopkins and Trump, he added: "They seek to divide at a time we need to come together".
The Metropolitan Police said 14 people - including several boys and a girl - have been arrested in connection with the incidents in Wandsworth, Plumstead and Clapham.
Police in Tower Hamlets after a man died after a stabbing.
Khan is addressing these causes of knife crime directly, creating the Violence Reduction Unit to take a public health approach to knife crime, establishing the Young Londoners Fund to support services for young people and championing fair housing measures such as community land trusts to reduce wealth inequality.
Another three men were slashed in a separate knife attack at about 3am on Saturday.
Mr Khan said he was "sickened" by the deaths and London's Met Police said "bearing down on violent crime" in the capital remained "their top priority".
According to the murdermap project, which tracks homicides in London, 59 murders have been recorded in the British capital so far in 2019.