USA diplomats are expected to move in to the new quarters this month.
According to the White House, the president chose to cancel his plans because he was angry with the deal the Obama administration made to get the new embassy built, and is instead sending Secretary of State Rex Tillerson in his place.
On the embassy web page about the project, it said: "The project has been funded entirely by the proceeds of the sale of other US Government properties in London, not through appropriated funds".
His freakish excuse comes amid claims he feared mass street protests on his arrival and had previously insisted he would visit when he had the support of the people.More news: Bears hire Mark Helfrich as offensive coordinator
Trump confirmed that he had cancelled the visit in a tweet sent late on Thursday, but said it was due to his displeasure over the location of the new embassy. The Daily Mail reported that Trump had backed out because he was unhappy about arrangements for the visit, which was billed as a "working" visit rather than a full state visit that could include a meeting with Queen Elizabeth.
It said some officials believed he decided not to come because he felt the arrangements for the visit were too low key, and would instead send Secretary of State Rex Tillerson to open the embassy.
Mr Khan, who also questioned Mr Trump's proposed U.S. travel ban, said the USA president's visit would "without doubt have been met by mass peaceful protests".
Plans for a state vist were postponed past year following large street protests in London and across the country.
Donald Trump has cancelled his visit to the United Kingdom, amid fears that he would be met with huge protests.More news: Facebook Dismisses Claim WhatsApp Chat Groups Can Be Infiltrated
The mayor also criticized Prime Minister Theresa May for having extended a state visit invitation to Trump last January.
"The opening of the US Embassy is a matter for the US". He said Donald Trump "got the message" that many Londoners opposed the visit.
Mr Trump's decision not to come to the country comes despite Prime Minister Theresa May saying that a future visit was still on the cards last week.
President Trump fired off a series of critical tweets over Khan's handling of the attack, mocking the mayor's comments that there was "no reason to be alarmed" over armed police on the streets.More news: Amid injury fears Guardiola warns hectic schedule will "kill" players
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