Authorities across the US have boosted security at places of worship following a shooting at a synagogue in Pittsburgh which killed 11 people.
Robert Bowers, 46, is accused of opening fire at the Tree of Life synagogue during its Sabbath service.
Religious institutions in New York City, Los Angeles, Chicago and Philadelphia were subject to extra patrols.
Six people were injured in Saturday’s attack.
Bowers faces 29 criminal counts, including use of a firearm to commit murder, in what is believed to be the worst anti-Semitic attack in recent US history.
Federal prosecutors say they will also file hate crime charges, and the suspect could face the death penalty.
President Donald Trump described the attack as a “wicked act of mass murder”.
The Israeli prime minister, Benjamin Netanyahu, said everybody should stand up and fight back against anti-Semitism.
The country’s weekly cabinet meeting opened with a moment of silence in solidarity with the victims of the attack.
Hundreds of people – from the neighbourhood and also all across Pittsburgh – gathered for an interfaith vigil for the victims of the attack in the synagogue in Squirrel Hill.
Sophia Levin, a local resident and one of the organisers, told the BBC people wanted to be “together, not alone”, and the vigil would help heal the city.
President Trump said he would visit Pittsburgh soon. He also ordered US flags at government buildings to be flown at half-mast until 31 October.
On Saturday morning, worshippers had gathered at the synagogue for a baby naming ceremony during the Sabbath.
Squirrel Hill has one of the largest Jewish populations in Pennsylvania and this would have been the synagogue’s busiest day of the week.
Police said they received first calls about an active shooter at 09:54 local time (13:54 GMT), and sent officers to the scene a minute later.
According to reports, Mr Bowers, a white male, entered the building during the morning service armed with an assault rifle and three handguns.
The gunman had already shot dead 11 people and was leaving the synagogue after about 20 minutes when he encountered Swat officers and exchanged fire with them, FBI agent Robert Jones said.
The attacker then moved back into the building to try to hide from the police.
He surrendered after a shootout, and is now being treated in hospital for what has been described as multiple gunshot wounds.
The crime scene was “horrific”, Pittsburgh’s Public Safety Director Wendell Hissrich told reporters. “One of the worst I’ve seen, and I’ve [worked] on some plane crashes. It’s very bad.”
Mr Hissrich said no children were among the casualties.
US media said he had shouted “All Jews must die” as he carried out the attack.
Social media posts by someone with the name Robert Bowers were also reported to be full of anti-Semitic comments.
