There was an outpouring Saturday of condemnation for anti-Semitism and support for the Jewish community affected by the mass shooting at the Tree of Life synagogue, where 11 people were killed and six injured after a gunman opened fire after reportedly yelling "all Jews must die."

President Trump decried anti-Semitism in the statements on the massacre that opened his speech at a campaign rally in Murphysboro, Ill.

"This evil anti-Semitic attack is an assault on all of us. It is an attack on humanity. It will require all of us working together to extract the hateful poison of anti-Semitism from our world," he told the crowd gathered in an airplane hangar.

Trump called for the death penalty in the incident and said anti-Semitism cannot be ignored or tolerated.

But anti-Semitism has seen a resurgence in recent years. The Anti-Defamation League reported that anti-Semitic incidents were up 57 percent over 2016, including a number of bomb threats to Jewish congregations in the first quarter of that year.

Trump's comments came after his daughter, White House adviser Ivanka Trump, issued a statement condemning the attacks, calling them "the acts of a depraved bigot and anti-Semite." She and her husband, Jared Kushner, are Jewish.

[More: Jim Mattis: Pittsburgh synagogue shooter the 'poorest excuse for a man']

Rabbis Marvin Hier and Abraham Cooper of the California-based human rights organization the Simon Wiesenthal Center called on Trump "to immediately convene an emergency meeting of religious leaders to help stop the slide to extremism," according to a joint statement issued by the center.

“Americans need and want leadership from both sides of the political aisle to stop the continuous slide to the brink," the statement reads.

Far-right protesters at the Unite the Right rally in Charlottesville, Va., chanted "Jews will not replace us" and other anti-Semitic slogans in August 2017, though the rally was intended in part to protest the removal of a Confederate monument to Robert E. Lee. A counterprotester, Heather Heyer, was killed when a man deliberately drove his car into the crowd.

Trump, who in the aftermath of the Charlottesville riot pointed to good people on both sides, unequivocally condemned anti-Semitism on Saturday.

"It must be confronted and condemned everywhere it rears its ugly head. We must stand with our Jewish brothers and sisters to defeat anti-Semitism and vanquish the forces of hate," he said in Illinois on Saturday.

Prime minister of Israel Benjamin Netanyahu also decried the incident, saying he and the people of Israel grieve with the families of those killed in the shooting and stand with the American people "in the face of this horrendous anti-Semitic brutality."

Other U.S.-based Jewish groups, including the Anti-Defamation League, were quick to condemn the anti-Semitic incident.

"We believe this is the deadliest attack on the Jewish community in the history of the United States," read a statement from the ADL.

"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 organization stated. In addition to weekly holy day services, many people at the synagogue were reportedly there to celebrate a naming ceremony for a baby boy.

The ADL also highlighted increases in anti-Semitic online harassment. A social media profile on the platform Gab, popular with members of the alt-right, bearing the name of the shooter, had shared anti-Semitic images and sentiments prior to the shooting.

The profile, which has not been confirmed as belonging to Bowers, was suspended by Gab following the shooting. The Twitter-like alternative social network touts itself as a platform for free speech.

A statement from the United States Holocaust Memorial Museum called on all Americans to promote social solidarity.

"The Museum reminds all Americans of the dangers of unchecked hatred and antisemitism which must be confronted wherever they appear," read a statement from the Washington, D.C.-based organization.