Obama calls for unity on 15th anniversary of 9/11 attacks

U.S. President Barack Obama has urged Americans to remain united in the face of terrorist attacks 15 years after 9/11 and vowed that his government will keep doing everything to protect the homeland.

Obama, who was speaking in his weekly radio and online address delivered on the eve of the 15th anniversary of the September 11 terror attacks, said how America responds in the face of terrorism matters.

"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. It's what makes us resilient.And if we stay true to those values, we'll uphold the legacy of those we've lost, and keep our nation strong and free," abc.net.au quoted him as saying.

Obama has on several occasions also denounced Republican presidential nominee Donald Trump's bombastic rhetoric towards Muslims.

After the December shooting rampage in San Bernardino, California, Trump had called for a temporary ban on the entry of Muslims to the country.

Obama said the U.S. cannot give in to those who would divide it, adding its diversity and welcoming of all talent is what makes the country resilient.

His remarks on Trump came two months before the presidential election in which the real estate magnate will face Democratic presidential nominee Hillary Clinton.

Obama also noted that much had changed over the past 15 years since the attacks.

"We delivered justice to [Al-Qaeda leader] Osama bin Laden. We've strengthened our homeland security. We've prevented attacks. We've saved lives," he said.

He, however, asserted that the terrorist threat has evolved.

Obama vowed to destroy terrorists to protect his homeland.

"So in Afghanistan, Iraq, Syria and beyond, we'll stay relentless against terrorists like Al-Qaeda and [the Islamic State group] ISIL...We will destroy them. And we'll keep doing everything in our power to protect our homeland," he said.

More than 2,750 people were killed when two passenger jets destroyed the Twin Towers on September 11, 2001.

While another jet slammed into the Pentagon, a fourth jet crashed in a field in Pennsylvania after those on board tried to overpower the hijackers.