London (CNN)Police in London are investigating anti-Semitic graffiti found scrawled across shop fronts, restaurants and a synagogue as a possible hate crime.
Images of the Star of David and messages apparently relating to the September 11 attacks were painted on buildings in the north of the city on Saturday evening, authorities said.
"This is clearly a concerning incident and one we are taking seriously," inspector Kev Hailes said in a statement. "We have liaised with our partners in order to remove the graffiti and various enquiries are underway to find who is responsible."
According to the statement, no arrests have yet been made.
Residents posted photos online of the graffiti, which appeared in several different locations in the Hampstead and Belsize Park areas.
The South Hampstead Synagogue, located in a part of London with a large Jewish population, was also targeted.
James Sorene, the CEO of the Britain Israel Communications and Research Centre, said on Twitter that the targets include an "Israeli style cafe" that recently closed down.
The numbers "911" refer to the anti-Semitic conspiracy theory that Jewish people were responsible for the September 11 attacks in New York, Sorene added, describing the grafitti as "chilling."
Reports of anti-Semitic incidents have spiked in the UK this year, according to the Community Security Trust charity that monitors anti-Semitism in Britain.
The group said there were 892 recorded incidents in the first six months of 2019 -- a 10% increase compared to the same period last year and the highest number for the same period since records began in 1984.
The incidents in London came on the same day five people were stabbed at a Hanukkah celebration in New York.
New York Gov. Andrew Cuomo said the stabbing was "the latest in a string of attacks against members of the Jewish community in New York this week."