Violent attacks against the Jewish community in the United States doubled last year, the Anti-Defamation League (ADL) reported Tuesday. Overall attacks that also included vandalism and harassment remained near record-high levels.

The Jewish civil rights group counted 39 cases of physical assaults involving 59 victims in 2018, up from 19 assaults and 21 victims in 2017. The 2018 tally includes 11 people who were killed and two congregants wounded when a gunman opened fire at the Tree of Life Synagogue in Pittsburgh in October -- the deadliest attack on Jews in the nation's history.

In addition to that shooting, 2018 "saw high levels of white supremacist activity, including propaganda on college campuses and in communities, and hateful robocalls aimed at voters," the ADL said.

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The New York-based group counted a total of 1,879 anti-Semitic incidents -- harassment, vandalism or physical assault -- in 2018. That is a 5 percent decrease from the 1,986 incidents reported in 2017, but the third-highest total since ADL began tracking the data in the 1970s. The 2017 number marked a 57 percent increase over 2016 and was the highest tally ADL had counted in more than two decades.

"It's clear we must remain vigilant in working to counter the threat of violent anti-Semitism and denounce it in all forms, wherever the source and regardless of the political affiliation of its proponents," said Jonathan Greenblatt, ADL's CEO and national director.

A total of 46 states saw anti-Semitic incidents.

People gather for a Community-Wide Solidarity Vigil at the Holocaust Memorial Miami Beach to remember the victims of the shooting at a Pittsburgh temple on October 30, 2018, in Miami Beach, Florida. Joe Raedle/Getty Images

The ADL released its findings three days after a gunman opened fire at a Southern California synagogue, killing a woman and wounding a rabbi and two others. Israel Dahan, whose 8-year-old daughter and brother-in-law were wounded at the Chabad of Poway synagogue near San Diego, said he doesn't understand why there's so much hate.

"We welcome everybody. We love everybody," said Dahan, 32, who is originally from Israel. "I don't even know why people like that (are) coming up against Judaism and against Jewish people."

In 2018, ADL counted 1,066 cases of harassment, defined as a situation in which a Jewish person or group of people "feel harassed by the perceived anti-Semitic words, spoken or written, or actions of another person or group." Last year's tally of harassment incidents was 5 percent higher than in 2017. The one category that experienced a decline was vandalism: The 774 incidents in 2018 represented a 19 percent drop from 2017.

"We've worked hard to push back against anti-Semitism, and succeeded in improving hate crime laws, and yet we continue to experience an alarmingly high number of anti-Semitic acts," Greenblatt said.

ADL's report says "known extremist groups or individuals inspired by extremist ideology" were responsible for 249 anti-Semitic incidents in 2018, accounting for 13 percent of the total.

"This is the highest level of anti-Semitic incidents with known connections to extremists or extremist groups since 2004, when at least 128 incidents were the result of leaflet distributions by white supremacist groups," the report adds.

ADL last year counted 140 anti-Semitic incidents that referenced Israel or Zionism, including dozens of robocalls from a white supremacist who ran an unsuccessful campaign for a U.S. Senate seat in California.

The report says ADL includes "anti-Israel incidents" in its audit of anti-Semitic incidents "if they invoke or are accompanied by classic anti-Semitic stereotypes and tropes (such as Jews/Zionists control the government), if they target Jewish religious or cultural institutions or if they are expressed by groups or individuals who consistently express anti-Semitic ideas."

"ADL is careful to not conflate general criticism of Israel or anti-Israel activism with anti-Semitism. However, Israel-related harassment of groups or individuals may be included when the harassment incorporates established anti-Jewish references, accusations and/or conspiracy theories," the report adds.