President Barack Obama, a voice of reason at a time of growing nationalism where each day seemingly unveils a new act of hatred, urged Americans “to fight the rise of anti-Semitism” after yesterday’s synagogue shooting in Pittsburgh left 11 people dead and others wounded.

“We grieve for the Americans murdered in Pittsburgh,” Obama said on Twitter Saturday night. “All of us have to fight the rise of anti-Semitism and hateful rhetoric against those who look, love, or pray differently. And we have to stop making it so easy for those who want to harm the innocent to get their hands on a gun.”

In his remarks, Obama referred to a gunman who opened fire at the Pittsburgh-area Tree of Life Synagogue Saturday morning. The suspect, 46-year-old Robert Bowers, has been charged with 29 federal counts including hate crimes, according to the USA Today. CBS affiliate KDKA said Bowers allegedly made the anti-Semitic comment “all Jews must die” before opening fire inside the synagogue. Authorities said Bowers had an assault rifle and four handguns.

Bowers was taken into custody and transferred to a hospital to treat wounds he received from a gunfight with officers.

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The hate crime is now believed to be the worst on worshipping Jewish people in American history, according to Cincinnati professor and director of the American Jewish Archives, Dr. Gary P. Zola. Pennsylvania Attorney General Josh Shapiro said the shooting occurred while congregants were at the synagogue for a baby-naming ceremony.

“It’s a very horrific crime scene. It’s one of the worst that I’ve seen,” Pittsburgh Public Safety Director Wendell Hissrich said at a press conference Saturday afternoon.

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The Anti-Defamation League said in a statement that the attack was “likely the deadliest attack on the Jewish community in the history of the United States.”

“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 group said in the statement.