President Barack Obama Speaks On 15th Anniversary Of Sept. 11 Attacks

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Sunday marked the 15th anniversary of the deadly Sept. 11 terrorist attacks in 2001, and President Barack Obamaencouraged Americans to honor the lives lost by standing true to America's values.

In a speech on Sunday morning at the Pentagon Memorial inWashington D.C., Obama spoke to hundreds of service members, relatives and survivors of the attacks. Terrorists from the group al-Qaeda hijacked four passenger airlines, crashing planes into the two towers of the World Trade Center, the Defense Department headquarters of the Pentagon, and a field in Pennsylvania.About 3,000 people were killedas a result of the attacks.

During his final 9/11 speech as President of the United States, Obama said that the threat of terrorism has evolved in the 15 years since the attacks.He also noted that part of the United States' response was military forces' killing of al-Qaeda leader Osama bin Laden duringa raid in Pakistan that Obama authorized.

"Wecontinue doing everything in our power to protect this country that we love," Obama said, according to a report by Associated Press.He encouraged Americans to honor the lives lost by 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."

"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."