WASHINGTON (AP) -- President Barack Obama on Sunday marked the 15th anniversary of the Sept. 11 attacks by calling on Americans to embrace the nation's character as a people drawn from every corner of the world, from every religion and from every background. He said extremist groups will never be able to defeat the United States.
Obama spoke to hundreds of service members, and relatives and survivors of the attack that occurred at the Pentagon when American Airlines Flight 77 slammed into the Defense Department's headquarters, killing 184 people. The youngest victim was only 3 years old. In all, about 3,000 people lost their lives that day as a result of the planes that crashed into New York City's World Trade Center and in a Pennsylvania field.
The president said extremist groups such as the Islamic State group and al-Qaida know they can never drive down the U.S., so they focus on trying to instill fear in hopes of trying to get Americans to change how they live.
"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. "This is the America that was attacked that September morning. This is the America that we must remain true to."
Obama spoke on warm, sunny morning, noting that the threat that became so evident on Sept. 11 has evolved greatly over the past 15 years. Terrorists, he said, often attempt attacks on a smaller, but still deadly scale, specifically citing attacks in Boston, San Bernardino and Orlando as examples.
In the end, he said, the enduring memorial to those who lost their lives that day is ensuring "that we stay true to ourselves, that we stay true to what's best in us, that we do not let others divide us."
"How we conduct ourselves as individuals and as a nation, we have the opportunity each and every day to live up to the sacrifice of those heroes that we lost," Obama said.
Obama began and ended his remarks by quoting from the Book of Proverbs: "Let not steadfast love and faithfulness forsake you. Bind them around your neck. Write them on the table of your heart."
Obama also marked his final Sept. 11 observance as president with a moment of silence inside the White House to coincide with when the first plane hit the Twin Towers. Atop the White House, the American flag flew at half-staff. Obama invited governors, interested organizations and individuals to follow suit.
A decade after the attacks, al-Qaida leader Osama bin Laden was killed by U.S. forces in a raid in Pakistan that Obama authorized. Obama noted that event as he spoke about how the nation has responded since 9/11 by delivering "justice" to bin Laden, by strengthening homeland security and by preventing attacks.
"We resolve to continue doing everything in our power to protect this country that we love," he said, facing the crowd and the benches that are a hallmark of the Pentagon Memorial.