The shooting at the Tree of Life synagogue in Pittsburgh — in which the death toll now stands at 11 — is believed to be the deadliest attack on the Jewish community in the history of the US, the Anti-Defamation League said.

"It is simply unconscionable for Jews to be targeted during worship on a Sabbath morning, and unthinkable that it would happen in the United States of America in this day and age," the Jewish organization, which tracks anti-Semitic incidents, said in a statement.

Until now, the deadliest attack specifically targeting Jews happened in 1985 when a Seattle lawyer Charles Goldmark was bludgeoned and stabbed to death, along with his wife, Annie, and their two sons, the ADL said. David Morse Rice, a drifter and unemployed steelworker, was found guilty of those killings.

Anti-Semitic incidents and online harassment rising, ADL says

The ADL said the attack Saturday comes at a time when both anti-Semitic incidents and online harassment are on the rise.

Jewish people were the victims of more reported hate crimes than any other religious minority in 2016, according to the most recent year of FBI statistics.

In that year, 684 anti-Jewish incidents were reported. That's more than the rest of religiously motivated hate crimes combined, records reveal.

Tracking such crimes can be nuanced and difficult. The motivations aren't always clear, and the crimes are often not reported by victims and police.

Robert Bowers, 46, faces 29 charges in all, including 11 counts of using a firearm to commit murder and multiple counts of two hate crimes: obstruction of exercise of religious beliefs resulting in death and obstruction of exercise of religious beliefs resulting in bodily injury to a public safety officer.

"The crimes of violence are based upon the federal civil rights laws prohibiting hate crimes," US Attorney Scott W. Brady and Bob Jones, FBI special agent in charge of Pittsburgh office, said in a statement.

The FBI, which calls an offense a hate crime when there's an added element of bias, is leading the investigation into the attack.

Bowers told a SWAT officer that he wanted all Jews to die and also that Jews were committing genocide to his people, according to CNN affiliate WTAE, citing a police criminal complaint filed Saturday evening in Pittsburgh.

Last year, The Anti-Defamation League reported, anti-Semitic incidents rose almost 60%, the largest single-year increase on record.

The ADL found 1,986 cases of harassment, vandalism or physical assaults against Jewish people or institutions in 2017. It found 1,267 in 2016.

"We're definitely in a period in our country where there's a general decrease in civility," Aryeh Tuchman, associate director for the ADL's Center on Extremism, said when the ADL released its findings in February. "People in the past who have tamped down their anti-Semitic proclivities may feel more liberated to express them than before."

'An escalating scourge of hate-based violence'

In a statement condemning the Pittsburgh attack, the Rabbinical Assembly said the shooting was a reminder that anti-Semitism "is on the rise in America at a rate unprecedented in decades."

"This vicious hate crime, perpetrated against innocent people at prayer is but the latest in an escalating scourge of hate-based violence in America," it said.

Moishe Bane, president of the Orthodox Union, expressed heartbreak for "the senseless murder of our fellow Jews and all victims of vicious hate crimes."

"We condemn the dangerous rhetoric that foments such senseless violence and we stand with the Tree of Life Congregation and the whole Pittsburgh community at this terrible time," he said.

Rabbi Elazar Muskin, president of the Rabbinical Council of America said "fringe elements of society" had become "emboldened by speech which is often disrespectful and hateful."

FBI says reports of hate crimes have increased

The FBI showed an overall increase in reported hate crimes of more than 4% from 2015 to 2016.

Anti-Islamic (anti-Muslim) crimes accounted for 307, up 19% from the previous year. That was the biggest percentage rise.

The FBI also tracks religiously motivated crimes against Eastern Orthodox Christians, other Christians, Hindus, Sikhs, Mormons, Jehovah's Witnesses and Buddhists.

In race categories, African Americans were targeted the most -- in about half of the reported 3,489 racially driven incidents in 2016.

The FBI said 1,200 incidents were motivated by bias against victims based on sexual orientation or gender identity.