An explicit video posted to YouTube showing a group of people attacking a synagogue in London at around 1:20am on Sunday morning.
A Scotland Yard spokesman said the men and women had left a nearby party, and that some of them were intoxicated.
Worshippers inside the Ahavas Torah synagogue in Stamford Hill were marking the end of the Sabbath when the assault occurred. The mob hurled anti-Semitic insults and threw chairs into the synagogue, breaking windows.
"I came down and there was a huge group of people, men and women, trying to force their way into the synagogue," a member of a Jewish civilian patrol, or Shomrim, said.
"The window had already been smashed. Teenagers were shouting abuse. It was blatantly anti-Semitic, they came and attacked a synagogue," the man continued. "I have clear footage which I'm going to show to the police, which clearly shows there were anti-Semitic chants."
Witnesses say the mob chanted "Kill the Jews," as they attempted to take over the building. The violence was captured on multiple cell phone video cameras and given to police.
Scotland Yard reported that four men and two women were arrested in connection with the vandalism.
The area's Jewish community has been uneasy following a record 1,168 anti-Semitic incidents in the United Kingdom last year. The figure was recently released in the Community Security Trust's annual report, and is more than double numbers in 2013.
An increase in anti-Semitic crimes was reported in the weeks following a deadly attack by an Islamic militant at a kosher grocery store in Paris, and Britain's former chief rabbi said that the citizens are afraid.
"After what happened in Paris, you are beginning to get British Jews asking, 'Will I be safe going to synagogue or going to a Jewish shop? Will my children be safe in a Jewish school?'" Lord Jonathan Sacks told Sky News.
Authorities do not believe Sunday's attack was related to religious extremism.