New York's governor says a knife attack by an assailant who burst into a party at a Hasidic rabbi's home and stabbed five people was an act of domestic terrorism.
Visiting the scene in Rockland County, about 48km north of New York City, Governor Andrew Cuomo met on Sunday with victims who had been attending the Hanukkah celebration at the home of Rabbi Chaim Rottenberg.
"This is terrorism, it is domestic terrorism," Mr Cuomo told reporters. "These are people who intend to create mass harm, mass violence, generate fear based on race, colour, creed."
He said he wanted New York to become the first US state to have a domestic terrorism law.
Local media reported that on Sunday night, knifing several people before fleeing.
Police work at the home of a rabbi on after a man entered the house and stabbed multiple people. Source: The Journal News
Authorities said the suspect, 37-year-old Grafton Thomas from Greenwood Lake, New York, was arrested in Manhattan after fleeing the site of the attack late on Saturday in the small town of Monsey.
He was arraigned on five counts of attempted murder and ordered held on $US5 million ($A7 million) bail, Ramapo town supervisor Michael Specht said on Twitter. Thomas is due back in court on 3 January.
President Donald Trump called it a horrific attack.
"We must all come together to fight, confront, and eradicate the evil scourge of anti-Semitism," Mr Trump wrote on Twitter.
Onlookers, many of them Orthodox Jewish, stand on the street from where five people were stabbed at a Hanukkah celebration. Source: FR171683 AP
Last year, - the deadliest attack against the Jewish community in the United States.
Earlier this month , which authorities said was fuelled in part by anti-Semitism.
A report in April from the Anti-Defamation League stated that the number of anti-Semitic attacks in 2018 was close to the record of 2017, with 1879 incidents.
"I was praying for my life," witness Aron Kohn said, comparing the knife used by the attacker to "the size of a broomstick".
Mr Kohn threw chairs and tables in an attempt to head off the assault.
"I saw him stabbing people," he added. "He injured a guy, he was bleeding in his hand, all over."
Mr Kohn said the attacker tried to enter the adjacent synagogue, but it was locked.
Extra patrols
Yossi Gestetner, of the Orthodox Jewish Public Affairs Council, told The New York Times that one of the victims was a son of the rabbi.
"The house had many dozens of people in there," Mr Gestetner said. "It was a Hanukkah celebration."
Rockland has the largest Jewish population per capita of any US county, with 31.4 per cent, or 90,000 Jewish residents.
In response to the recent surge in hate crimes in New York, Mayor Bill de Blasio had announced on Friday that the NYPD was stepping up patrols in three neighbourhoods and increasing the number of visits to places of worship.
After Saturday's attack, the mayor also tweeted that he has recently spoken to longtime Jewish friends who are fearful of outwardly showing their faith.
"We will NOT allow this to become the new normal," he wrote. "We'll use every tool we have to stop these attacks once and for all."
In Israel, Prime Minister Benjamin Netanyahu said the country "strongly condemns the recent displays of antisemitism including the vicious attack at the home of a rabbi in Monsey, New York."
"We will cooperate however possible with the local authorities in order to assist in defeating this phenomenon."
The attack happened on the seventh night of Hanukkah.
"It's a wave and a trend of hate-filled violence that is sweeping the country, not just NY State," tweeted Maya Wiley, a civil rights activist and senior vice president for social justice at the New School private university in New York. "We have to stand together to keep our neighbours safe."
