WASHINGTON -- President Barack Obama called on Americans to "reaffirm our character as a nation" as he marked the 15th anniversary of the 9/11 terror attacks during a ceremony outside the Pentagon on Sunday.
Defense Secretary Ash Carter and Chairman of the Joint Chief of Staff Gen. Joseph Dunford joined Obama in the commemoration at the National 9/11 Pentagon Memorial, outside the location of the building that was hit by a terrorist-hijacked plane.
"We honor the courage of those who put themselves in harm's way to save people they never knew. We come together in prayer and in gratitude for the strength that has fortified us across these 15 years. And we renew the love and the faith that binds us together as one American family," Obama said.
The Pentagon attack killed 184 people, including workers inside the building and passengers from hijacked American Airlines Flight 77, which crashed into it.
Obama praised the country's diversity during his remarks, calling it a strength and not a weakness.
"We know that our diversity, our patchwork heritage, is not a weakness. It is still and always will be one of our greatest strengths," Obama said. "The most enduring memorial to those we lost is ensuring the America that we continue to be. That we stay true to ourselves. That we stay true to what's best in us. That we do not let others divide us."
Obama also taped a special 9/11 message played by the NFL in stadiums before Sunday's 1 p.m. games. A similary message recorded by former President George W. Bush will air before the 4:25 p.m. games. He will also participate in the coin toss at the Cowboys-Giants game, with former first lady Laura Bush. And Obama and Bush will have a joint message air before the 8:30 p.m. game.
Vice President Joe Biden attended the Browns-Eagles game in Philadelphia, joining first-responders during pre-game dedications.