"This was an act of terrorism, designed to kill innocent people," Obama said of the attack by Syed Rizwan Farook and his wife Tashfeen Malik, that left 14 people dead, CNBC reports.

In what was only his third-ever Oval Office speech, the president outlined what authorities knew about the brutal attack in San Bernardino earlier this week, explaining that it was not yet known if the killers had been in contact with international terror networks, but that it was clear they had gone down "the dark path" of radicalization.

Read alsoCalifornia shooting: Farook appeared to have been radicalizedObama then turned to the "growing efforts" by terrorists to "poison the minds" of people, even if the terror groups don't offer specific directions on committing an attack.

In regard to these efforts, and other attempts to attack America, Obama pledged to "destroy ISIL [also known as the Islamic State, IS or ISIS] and any other organization that tries to harm us."

The president outlined how he planned to achieve this goal.

Read alsoCNN: U.S. forces may be given authority to capture ISIS terrorists"Our success won't depend on tough talk, or abandoning our values, or giving into fear — that's what groups like ISIL are hoping for," he said. "Instead we will prevail by being strong and smart, resilient and relentless, and by drawing upon every aspect of American power."

But he also called on Congress to make sure that no one on a "no-fly" list is able to purchase a gun. The no-fly list is maintained by the Federal Bureau of Investigation's (FBI) Terrorist Screening Center (TSC), and contains people who are not allowed to board a commercial aircraft to fly in or out of the country.

Obama also renewed his calls to make it more difficult for people to purchase "powerful" assault weapons.

And he called on the legislature to vote for the authorization for use of force in the war against the Islamic State. Obama, however, emphasized that he did not seek an extended ground war against the radical group. He said that the current strategy of airstrikes and special forces would allow for a more sustainable victory.

The president is keen for Silicon Valley to help address the threat of Islamic State and other militant groups that use social media and electronic communications to plan and promote attacks.

Read alsoCNBC: Obama calls on EU to share airline intelligence info"I will urge high-tech and law enforcement leaders to make it harder for terrorists to use technology to escape from justice," Obama said in the televised speech. This could reignite debate about the government's digital surveillance programs.

The president also stressed that it was "the responsibility of all Americans" to reject discrimination.

"When we travel down that road, we lose," Obama said, saying that calls for religious tests and other measures against Muslims played "into the hands of groups like ISIL."