President Obama will discuss the San Bernardino, Calif., shootings and the broader threat of terrorism on Sunday night in a rare prime time address from the Oval Office.

The address at 8 p.m. will hit on the Islamic State in Iraq and Syria (ISIS or ISIL) and how the terror threat has "evolved, and how we will defeat it," according to the White House.

"He will reiterate his firm conviction that ISIL will be destroyed and that the United States must draw upon our values – our unwavering commitment to justice, equality and freedom – to prevail over terrorist groups that use violence to advance a destructive ideology," the White House said in a statement Saturday night.

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It is rare for the president to give a prime-time speech from the Oval Office, with Obama preferring instead to address the nation from the East Room.

He has made only two formal addresses from the Oval Office during his presidency, with the last one coming in 2010 to mark the end of combat troops in Iraq.

The speech will come less than a week after 14 people were killed and dozens injured during a shooting in San Bernardino, which is being investigated as an act of terrorism. It is also less than a month after the terrorist attacks in Paris, for which ISIS claimed responsibility.

Obama called the California shootings an act of terrorism earlier Saturday and said it is possible the two shooters were radicalized.

"It is entirely possible that these two attackers were radicalized to commit this act of terror,” Obama said during his weekly address. “And if so, it would underscore a threat we’ve been focused on for years — the danger of people succumbing to violent extremist ideologies."

During a briefing with national security aides, Obama was told there were no links yet uncovered to a broader terrorist cell. The Islamic State in Iraq and Syria has increasingly encouraged lone wolf attacks.

The two suspects behind Wednesday’s attack in California, Syed Farook and Tashfeen Malik, were not on any government watch list. Shortly ahead of the attack on Wednesday, Malik is believed to have posted a Facebook message pledging allegiance to ISIS leader Abu Bakr al-Baghdadi.

The Oval Office address also comes as the president is facing increasing pressure over the threat from ISIS.

Critics say Obama has underestimated the group, noting earlier remarks mocking the group as a "JV team" and claiming they had been "contained."

The White House later said Obama meant that the group's geographic advance in Iraq and Syria had been stopped.

In an interview on Thursday, Obama expressed confidence, telling the public that law enforcement was vigilant against any threats from ISIS.

"What I try to do is to make sure that people understand the threat is real, we have to be vigilant, but we also can't panic and we can't respond out of fear," Obama told CBS News.

Obama spoke with France President Francois Hollande on Friday to update him on the California shooting, and to pledge continued cooperation in fighting terrorism.

Lawmakers on Capitol Hill have debated a number of policies in the wake of the Paris attacks last month, including increased screening for refugees and strengthening screening in the U.S. visa waiver program.

This story was updated at 7:38 p.m.