Five people have been stabbed at the home of a rabbi in New York state.
The attack happened on the seventh night of the Jewish festival of Hanukkah.
The attack took place just before 10pm (3am Irish time) at a house in Monsey around 48km from New York City.
The Orthodox Jewish Public Affairs Council (OJPAC) said two of the victims were critically injured.
It is believed the attacker fled the scene after failing to gain entry to an adjacent synagogue.
Ramapo Police Chief Brad Weidel later confirmed that a suspect had been arrested.
Photos and videos posted on social media show a large emergency response with paramedics running and pushing stretchers.
New York City's police department said it was stepping up patrols in heavily-populated Jewish neighbourhoods following a rise in anti-Semitic attacks.
New York Governor Andrew Cuomo described the “latest in a string of attacks against members of the Jewish community in New York as a “despicable and cowardly act.”
I am horrified by the stabbing of multiple people at a synagogue in Rockland County tonight.
We have zero tolerance for anti-Semitism in NY and we will hold the attacker accountable to the fullest extent of the law.
NY stands with the Jewish community. pic.twitter.com/JILUoFXJc9
— Andrew Cuomo (@NYGovCuomo) December 29, 2019
He said the New York State Police hate crimes task force would take control of the investigation.
“Let me be clear: antisemitism and bigotry of any kind are repugnant to our values of inclusion and diversity and we have absolutely zero tolerance for such acts of hate,” he said.
“In New York we will always stand up and say with one voice to anyone who wishes to divide and spread fear: you do not represent New York and your actions will not go unpunished.”
New York Mayor Bill de Blasio tweeted: "Hate doesn't have a home in our city," describing the latest incident as an attack on all New Yorkers.
With reporting from IRN ...