Images have been released of three men police want to speak to about allegations of anti-Semitic abuse directed at Jewish passengers on a bus.
A group was filmed approaching the privately hired bus on Oxford Street in central London on Monday.
Footage shows men spitting at the bus and apparently abusing passengers. Prime Minister Boris Johnson has described the video as "disturbing".
Det Insp Kevin Eade said police were treating the incident as a hate crime.
In the video, which was posted on social media, a man seems to make a Nazi salute and others wave their shoes - an insult in some countries.
Det Insp Eade said: "This was a deeply upsetting incident for a community group who were celebrating the Jewish festival, Hanukkah.
"There is no place in our city for hate crime. Everyone should be able to enjoy their lives without harassment and I urge anyone who can name the individuals pictured to contact police without delay."
The initial BBC report said a slur about Muslims could also be heard coming from inside the bus. This claim has been disputed. (You can see details about the BBC's response to that dispute below.)
The Met Police has said the incident will be looked at "in its entirety".
Tamara Cohen, who was on the bus, said she did not hear anyone saying anything provocative to the group of men gathered outside the vehicle.
She described the group initially "standing around watching and making fun" of those on the bus.
Ms Cohen added: "Then as it went on they started getting really aggressive, shouting and being abusive.
"We wanted to leave but couldn't because of the traffic.
"That's when they came up to the bus and started banging on the bus with their shoes, swearing and shouting at us and making gestures.
"It was all really intense."
The Met Police said officers were deployed to investigate after the incident was reported on Monday. They met the bus in Grosvenor Place and spoke to the occupants.
A spokesman added: "The group shown in the video could not be located at the time of the incident and there have been no arrests."
However, Ms Cohen said she was disappointed by the police response.
She added: "They said they couldn't do anything at the time because there was no actual violence that happened. That's kind of ridiculous.
"I do feel like it was only after the video got more attention online that I started to see that the police started to take it more seriously.
"That's pretty disappointing. They should have done something sooner."
The President of the Board of Deputies of British Jews, Marie van der Zyl, called for swift arrests.
She said: "We are appalled by the horrifying footage of Jewish people targeted on Oxford Street.
"We note that besides attempts to spit at them, at least one of the perpetrators appears to be performing a Nazi salute."
Correction 3 December: During the editing process a line was added to this article reporting that racial slurs about Muslims could be heard inside the bus. This line has been amended to make clear that "a slur about Muslims" could be heard.
Amendment 26 January 2022: The article published on 2 December 2021 included a line which said that slurs about Muslims could be heard coming from the bus. The article was amended the following day to say that only one such slur could be heard. Since publication of that amendment, the claim a slur could be heard has been disputed by Hebrew speakers and others. In response to criticism of the reporting the director general of the BBC instructed the Executive Complaints Unit (ECU), which is editorially independent from BBC News, to investigate a number of issues relating to the original reporting of the incident and the subsequent dispute over whether a slur could be heard.
You can read the ECU's findings here.