A Jewish leader in Washington, D.C., said on Monday that the killings of 11 people at a Pittsburgh synagogue will leave Jewish people in the United States feeling less safe.

"What we know from history is that when hatred does arise, then the Jewish community, by and large, tends to be the target," Gil Preuss, CEO of the Jewish Federation of Greater Washington, told Hill.TV's Buck Sexton and Krystal Ball on "Rising."

"People were asking themselves 'is this a new world we're living in right now? What do we need to do? How do we respond with security? How do we make sure that the children are protected? What does that look like?' " he continued.

"So we'll see what evolves over time, but at the moment at least, people see this as a shift in the dynamic of the level of security that the Jewish community feels within the United States," he said.

Eleven people were killed on Saturday at the Tree of Life Synagogue in the Squirrel Hill neighborhood of Pittsburgh in what is likely the worst incident of mass violence against Jewish people in U.S. history, according to the Anti-Defamation League. A lone suspect, Robert Bowers, was arrested on the scene.

His social media accounts showed a number of anti-Semitic posts, and he reportedly said he wanted to kill Jews when he was arrested.

Tree of Life Synagogue Rabbi Jeffrey Myers lamented what he called a growing hate against the Jewish community in an interview with NBC on Monday.

"Am I really experiencing this? Is this just some horrific nightmare and I’m going to wake up? Was this just some cruel drill the FBI had us do to practice?" Myers asked.

"All of those things go through simultaneously. And then I saw that there is hate and it isn’t going away. It just seems to be getting worse," he continued.

A study released on Friday by the Anti-Defamation League before the shooting found an increase in anti-Semitic images and other posts on Twitter and Instagram over the past year.

— Julia Manchester