Footage on social media showed a convoy of cars covered with Palestinian flags passing down Finchley Road, in north London, with passengers heard to shout offensive language and threats against Jews.
The Metropolitan Police said the vehicle involved had been identified and the force was making enquiries to locate the occupants.
“This sort of behaviour will not be tolerated,” the force said.
The footage, along with other incidents that have emerged following large pro-Palestine rallies over the weekend, has received cross-party criticism.
‘No place for anti-Semitism in our society’
Mr Johnson said: “There is no place for anti-Semitism in our society.
“Ahead of Shavuot, I stand with Britain’s Jews who should not have to endure the type of shameful racism we have seen today.”
Labour leader Sir Keir Starmer described the incident as “utterly disgusting.”
“Anti-Semitism, misogyny and hate have no place on our streets or in our society,” he said.
“There must be consequences.”
Mike Freer, MP for Finchley and Golders Green, said: “The scenes I’ve witnessed in my constituency today have left me sick to my stomach.
“The blatant and open anti-Semitism on display today, deliberately targeting areas with large Jewish populations is nothing short of incitement and I have urgently raised the matter with the Home Secretary, Commissioner and Mayor.”
Home Secretary Priti Patel also described the scenes as “disgusting anti-Semitism”.
“There is no place for this hatred in the UK,” she tweeted.
“I expect @metpoliceuk to be taking this seriously.”
Referring to the video of the convoy, Housing and Communities Secretary Robert Jenrick said: “This, on the streets of London, is deeply disturbing.
“Vile, criminal hatred like this must not be tolerated.”
In a statement Mr Jenrick continued: “Whatever your view of the conflict in Israel and Gaza, there is no justification for inciting anti-Jewish or anti-Muslim hatred.
“The incidents of anti-Semitism we have seen in recent days have been shameful.
“Some of the language used on marches this weekend and in posts on social media is intimidating, criminal and racist.
“We must not tolerate this vile, shameful hate in our country. These actions must stop.”
Cabinet minister Michael Gove described another video appearing to show protesters shouting anti-Semitic abuse as “deeply concerning”.