Six people were arrested after an incident at a Stamford Hill Synagogue that police are treating as an antisemitic attack.
A brawl broke out after party-goers leaving a house attacked local Jews in the early hours of Sunday morning.
Armed police rushed to the Ahavas Torah shul where a gang of youths attacked worshippers.
A video of the incident shows around 10 members of the synagogue having to defend themselves with chairs and makeshift clubs as the apparently drunk youths attempt to force their way in through a set of double doors.
The gang, which included two girls, are seen throwing missiles, smashing glass and threatening shul members who are barring their entry.
The gang is alleged to have shouted "kill the Jews".
Six men were held on public order offences. The men remained in custody on Sunday night.
Police said the attack was being treated as hate crime because of some of the language used by the youths. There was nothing to suggest it was a planned attack.
But Rabbi Maurice Davis, of Ahavas Torah, told the BBC: "I think the incident was more antisocial than antisemitic".
He said the attack started after a Jewish man was involved in a fight in the street and ran into the synagogue to seek refuge.
Stamford Hill is home to Europe's largest strictly Orthodox community.