Obama will give a prime-time address Sunday on terrorism and Islamic State

Reporting from Washington —  President Obama will deliver a rare prime-time address to the nation from the Oval Office on Sunday to outline his administration’s plans to combat terrorism and defeat Islamic State.

The speech will also provide an update on the federal investigation into Wednesday’s massacre in San Bernardino, which the FBI has described as an act of terrorism apparently inspired by the Sunni Muslim extremist group.

Since taking office in 2009, Obama has addressed the nation only three times from the Oval Office, the symbol of White House power. The last was Aug. 31, 2010, when he announced the withdrawal of all U.S. troops from Iraq in keeping with his campaign promise to end the war there.

Five years later, that speech appears to be a bittersweet moment in history.

Since mid-2014, Obama has sent about 3,500 troops back to Iraq to train and advise local security forces in the fight against Islamic State.

He is under intense pressure to further escalate efforts to break a yearlong military stalemate with the group, which continues to control vast areas, including some key cities, in Iraq and Syria.

Secretary of Defense Ashton Carter announced this week that about 200 more U.S. special operations troops would be sent to Iraq to conduct raids, gather intelligence and help step up the pace of airstrikes.

Although the militants have lost ground in recent months, they have expanded their global reach by conducting a deadly attack in Paris, downing a Russian passenger jet over Egypt and building up a new stronghold in Libya.

In the fiercely contested 2016 presidential race, Republican candidates have excoriated Obama’s counter-terrorism efforts as weak and ineffective, and called for stopping or restricting the immigration into the U.S. of Syrian refugees and others who they say could pose a danger.

In a statement announcing the speech, to air 8 p.m. Eastern time, the White House said Obama will seek to reassure the public that the government is taking effective steps to ensure their safety.

“The president will also discuss the broader threat of terrorism, including the nature of the threat, how it has evolved, and how we will defeat it,” the White House said. “He will reiterate his firm conviction that [Islamic State] will be destroyed.”

Authorities now believe Syed Rizwan Farook and his wife, Tashfeen Malik, were inspired to attack a festive holiday party at the Inland Regional Center on Wednesday by extremists’ online appeals.

Earlier Saturday, after Obama had been briefed by Atty. Gen. Loretta Lynch, FBI Director James B. Comey and other senior law enforcement and intelligence officials, the White House said authorities still had not turned up any evidence indicating the couple were part of a terrorist network.

FBI technicians are trying to reconstruct the couple’s digital footprints from partially destroyed computer hard drives, cellphones and their online accounts.

Investigators also are searching for signs the couple may have used encryption to hide messages.

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MORE ON THE SAN BERNARDINO SHOOTING:

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San Bernardino attack: What does Islamic State’s messaging mean?

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