President Obama said the 15th anniversary of the Sept. 11 terrorist attacks should serve as a reminder to Americans of the importance of diversity and warned against fear-mongering.

"In the face of terrorism, how we respond matters. We cannot give in to those who would divide us. We cannot react in ways that erode the fabric of our society," Obama said Saturday in the weekly White House address. "Because it's our diversity, our welcoming of all talent, our treating of everybody fairly — no matter their race, gender, ethnicity, or faith — that's part of what makes our country great."

The president's unifying message was a subtle jab at Republican nominee Donald Trump, who has spent the past 15 months criticizing Obama for not using the words "Islamic radicalism" when addressing terrorist attacks carried out by or tied to groups like the Islamic State and al Qaeda.

Obama praised his administration for the victories the Defense and State Departments have seen during his tenure.

"A lot has changed over these past 15 years. We've delivered devastating blows to the al Qaeda leaders that attacked us on 9/11. We delivered justice to Osama bin Laden. We've strengthened our homeland security. We've prevented attacks. We've saved lives," said Obama.

But for all of the successes he cited, Obama said national security continues to remain a top concern among American voters, where terrorist attacks and mass shootings have increasingly rocked the country in recent years.

"[T]he terrorist threat has evolved, as we've seen so tragically from Boston to Chattanooga, from San Bernardino to Orlando. So in Afghanistan, Iraq, Syria and beyond, we'll stay relentless against terrorists like al Qaeda and ISIL," Obama said. "We will destroy them. And we'll keep doing everything in our power to protect our homeland."