Donald Trump has been criticised for spreading the “hateful and divisive” rhetoric of Katie Hopkins as part of an attack on the mayor of London, Sadiq Khan.

The US president was widely condemned on Sunday for quoting the far right commentator as part of his latest broadside against Khan, whom he accused of being “a disaster” for the capital who would “only get worse!”.

He retweeted a Hopkins post in which she referred to London as “stab-city” and “Khan’s Londonistan” following the deaths of three men in separate attacks on Friday and Saturday.

Trump followed his message a few hours later with further criticism of Khan: “He is a national disgrace who is destroying the City of London!”

Donald J. Trump (@realDonaldTrump) LONDON needs a new mayor ASAP. Khan is a disaster - will only get worse! https://t.co/n7qKI3BbD2

While a spokesperson for Khan said he was not going to “waste his time” responding to the tweet, the Labour leader, Jeremy Corbyn, said it was “absolutely awful to see [Donald Trump] using the tragedy of people being murdered to attack the mayor”.

He wrote: “[Sadiq Khan] is rightly supporting the police to do their job while Katie Hopkins spreads hateful and divisive rhetoric. They seek to divide at a time we need to come together.”

Trump’s post followed the stabbing to death of a man in Wandsworth, south-west London, shortly before 4.45pm on Friday, while another man was shot dead in Greenwich, in the south-east of the capital, at about 5pm the same day. On Saturday afternoon, a man in his 30s was stabbed to death in Tower Hamlets, east London.

After the first two deaths Khan said he was “sickened to hear that two young lives have been ended within minutes of each other”. He added: “Our overstretched police are working around the clock to keep Londoners safe.”

A spokesman for the mayor said: “Sadiq is focusing on supporting London’s communities and overstretched emergency services. He has been in regular touch with senior Met police officers last night and throughout the day. His thoughts are with the victims’ families. He is not going to waste his time responding to this sort of tweet.”

The Muslim Council of Britain led calls for government figures to speak out against Trump’s decision to retweet Hopkins. A spokesman for the group said: “Whatever political differences our government or the Conservative party may have with Sadiq Khan, we would expect a clear and swift condemnation of Donald Trump’s consistent endorsement of British bigots.

“Once again the president of the United States has insulted the British people by sharing information from a well-known pedlar of hatred. This particular tweet points heavily to Islamophobic tropes against our capital city and its Muslim mayor.”

They pointed to the occasion in 2017 when Trump retweeted a handful of anti-Muslim videos posted by the deputy leader of the far-right group Britain First, an act that was criticised by the prime minister and home secretary.

“Silence on the issue is unacceptable for Muslim communities across the country, and demonstrates an alarming tolerance of Islamophobia in our country,” they said.

Naz Shah, a shadow equalities minister, said the fact that Trump could endorse people who use “racist tropes” and not provoke a response from the prime minister or Conservative party leadership candidates set a dangerous precedent.

“Minority communities are directly impacted when hatred and bigoted views are legitimised. Those communities will be looking at who will stand up for them?” she said. “So far, there is nothing but deafening silence from this Conservative government.”

Hopkins’ original tweet was posted alongside two screenshots of BBC News articles detailing the violence. She wrote: “20 hours in Stab-City UPDATE. 2 stabbed to death. 1 shot dead. Three stabbed - but not dead. Wandsworth & Tower Hamlets. This is Khan’s Londonistan.”

Timeline: Donald Trump’s feud with Sadiq Khan Read more

Trump’s hostility to Khan dates from 2015 when they were both fighting election campaigns and Khan criticised Trump’s presidential campaign pledge to ban Muslims from the US as “outrageous”.

The following May, Khan described Trump’s views on Muslims as “ignorant”, prompting Trump to challenge Khan to an IQ test. “I will remember those statements. They are very nasty statements,” said Trump.

In June 2017, after Trump was elected president, he falsely suggested in a tweet that Khan had said there was “no reason to be alarmed” after the terrorist attacks in Borough Market and London Bridge. Khan had actually said the public should not be alarmed by the increased police presence on London’s streets.

Khan then called on the government to cancel Trump’s state visit to the UK, saying “his policies go against everything we stand for”. His office gave permission for anti-Trump protesters to fly a protest blimp of Trump as a crying baby in a nappy.

Earlier this month, just before arriving in the UK, Trump described Khan as “a stone cold loser” and “very dumb”. He said Khan reminded him of the Democrat mayor of New York Bill de Blasio, “who has also done a terrible job – only half his height”.