President Barack Obama marked the anniversary of the Sept. 11 terrorist attacks on Saturday by calling on Americans “to stay true to who we are” as a way to honor the victims of the attacks.

“The highest honor we can pay those we lost, indeed our greatest weapon in this ongoing war, is to do what our adversaries fear the most: to stay true to who we are, as Americans,” Obama said during remarks at a wreath-laying ceremony at the Pentagon, where 184 people died in the attacks nine years ago. About 750 family members and service members attended Saturday’s ceremony.

Joined by Defense Secretary Robert Gates and Adm. Mike Mullen, Obama said that while Islamic extremists may try to spark conflict between different faiths, Americans “are not and never will be” at war with Islam.

“It was not a religion that attacked us that September day. It was al-Qaida, a sorry band of men which perverts religion,” he said. “Today we declare once more we will never hand them that victory. As Americans, we will keep alive the virtues and values that make us who we are and who we must always be.”

First lady Michelle Obama gave remarks at the site in Shanksville, Pa., where one of the hijacked planes on Sept. 11 crashed as passengers tried to wrest control from the terrorists.

“When we learned about the heroes of Flight 93 and what they had done, we were proud, we were awed, we were inspired. But I don’t think any of us were really surprised because it was clear that these 40 individuals were no strangers to service and to sacrifice,” the first lady said.

“For them, putting others before themselves was nothing new because they were veterans and coaches and volunteers of all sorts of causes,” she said. “To this day, they remind us … that being a hero is not just a matter of fate, it’s a matter of choice.”