President Donald Trump spoke at the Pentagon on Monday, remembering the victims of 9/11 and renewing America’s commitment to fighting terrorists.

“The terrorists who attacked us thought they could incite fear and weaken our spirit,” Trump said. “But America cannot be intimidated, and those who try, will soon join the long list of vanquished enemies who dared to test our mettle.”

The president attended the memorial with members of his staff, including Chairman of the Joint Chiefs of Staff Gen. Joseph F. Dunford Jr. and Defense Secretary Gen. James Mattis, who spoke at the ceremony.

Trump recalled that Americans came together on September 11, despite their differences, to send a message to the world.

“On that day, not only did the world change, but we all changed,” he reminisced. “Our eyes were opened to the depths of the evil we faced, but in that hour of darkness, we also came together with renewed purpose. Our differences never looked so small. Our common bonds never felt so strong.”

He paid tribute to the 184 lives lost at the Pentagon and the Americans aboard Flight 77, the plane that struck the building. He spoke to the victims’ families who were present for the memorial.

“I know that it’s with a pained and heavy heart that you come back to this place, but by doing so, by choosing to persevere through the grief, the sorrow, you honor your heroes, you renew our courage, and you strengthen all of us,” Trump said.

The president laid a wreath at the Pentagon Memorial and held a moment of silence for all of the victims of the 9/11 terrorist attacks.