President Trump told reporters ahead of a campaign rally that he will be traveling to Pittsburgh after the synagogue shooting that left 11 dead and six injured. Earlier Saturday, Mr. Trump called the shooting a "wicked act of mass murder" that was "pure evil and frankly unimaginable," and he declared that anti-Semitism "must be confronted anywhere and everywhere it appears."

With both the number of deaths and details of the synagogue's security still to be disclosed, Mr. Trump said gun control "has little to do with it" but "if they had protection inside, the results would have been far better."

After calling on the country to come together, he invited a pastor and rabbi on stage to pray. Mr. Trump also said he would continue with the events on his schedule Saturday because "we can't let evil change our life and change our schedule."

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"I will have a different tone tonight," Mr. Trump told reporters ahead of the nighttime rally. "I have a much different tone if the press was fair. I'm fighting their lack of honesty. We are making America great again. They are biased against me. We can soft coat it but that's the way it is."

At his first event, a speech to the Future Farmers of America, in Indianapolis, the president said he had considered canceling his appearance at a political rally Saturday evening in Illinois.

"At first, I was thinking I'll cancel, and then I said, 'You know, we can't let evil change our life and change our schedule.' We can't do that. We have to go and do whatever we were going to do," he said to applause. "Otherwise we given them too much credit. We make them too important and you go with a heavy heart, but you -- you go. You don't want to change your life. You can't make them important."

The president argued that after the 9/11 terrorist attacks in Manhattan in 2001, the New York Stock Exchange opened the "next day."

"I remember when we had the attack in Manhattan. We opened that stock exchange the next day. People were shocked," Mr. Trump recalled. "And the purpose wasn't financial, had nothing to do with financial, it's that we don't want to let people that are evil change are lives."

However, the NYSE did not open again until Sept. 17, 2001, six days after the attacks.

"So, I think when I'm finished with this, I should go to Illinois," Mr. Trump said. "I will go to Illinois and we'll keep our schedule the way its supposed to be," adding that "we should all do that."

Less than two weeks before elections for control of Congress, the shooting followed a tense week dominated by a mail bomb plot with apparent political motivations and served as another toxic reminder of a divided nation.

"A lot of people killed," Trump said upon his arrival in Indiana. "A lot of people very badly wounded." He said the attack "looks definitely like it's an anti-Semitic crime" and "there must be no tolerance for anti-Semitism in America."

But the attack did not persuade him that tighter gun controls are needed.

"This is a case where, if they had an armed guard inside, they might have been able to stop him immediately," Mr. Trump said. "Maybe there would have been nobody killed, except for him, frankly. So it's a very, very - a very difficult situation."

In previous mass shootings, the president has at times said he would consider tightening gun laws but in the main has called for more armed guards in places such as schools.

"The world is a violent world," he said before his speech. "And you think when you're over it, it just sort of goes away, but then it comes back in the form of a madman, a wacko. ... They had a maniac walk in and they didn't have any protection and that is just so sad to see, so sad to see."

Mr. Trump said lawmakers "should very much bring the death penalty into vogue" and people who kill in places such as synagogues and churches "really should suffer the ultimate price."

Rob Legare and Nicole Sganga contributed to this report.