President Barack Obama sought on Sunday to calm a nation put on edge by the California shootings, in a rare address to the nation on the threat posed by the Islamic State group.
Here are the most memorable quotes from Obama's address from the Oval Office, his third since coming to power:
We will destroy IS
"I know that after so much war, many Americans are asking whether we are confronted by a cancer that has no immediate cure."
"The threat from terrorism is real, but we will overcome it."
"We will destroy ISIL and any other organization that tries to harm us.... Our military will continue to hunt down terrorist plotters in any country where it is necessary."
Act of terror
The young Muslim couple who mounted the California attack "had gone down the dark path of radicalization, embracing a perverted interpretation of Islam that calls for war against America and the West."
"They had stockpiled assault weapons, ammunition, and pipe bombs. So this was an act of terrorism."
No broader conspiracy
"So far, we have no evidence that the killers were directed by a terrorist organization overseas or that they were part of a broader conspiracy here at home."
No war with Islam
"ISIL does not speak for Islam. They are thugs and killers. Part of a cult of death."
"We cannot turn against one another by letting this fight be defined as a war between America and Islam. That, too, is what groups like ISIL want.
"If we're to succeed in defeating terrorism, we must enlist Muslim communities as some of our strongest allies rather than push them away through suspicion and hate."
But Muslims must tackle extremism
"An extremist ideology has spread within some Muslim communities. It's a real problem that Muslims must confront without excuse.
"Muslim leaders here and around the globe have to continue working with us to decisively and unequivocally reject the hateful ideology that groups like ISIL and Al-Qaeda promote; to speak out against not just acts of violence, but also those interpretations of Islam that are incompatible with the values of religious tolerance, mutual respect, and human dignity."
And America must fight discrimination
"Just as it is the responsibility of Muslims around the world to root out misguided ideas that lead to radicalization, it is the responsibility of all Americans, of every faith, to reject discrimination.
"It is our responsibility to reject religious tests on who we admit into this country. It's our responsibility to reject proposals that Muslim-Americans should somehow be treated differently.... That kind of divisiveness, that betrayal of our values plays into the hands of groups like ISIL."
Urges gun control
"Congress should act to make sure no one on a no-fly list is able to buy a gun. What could possibly be the argument for allowing a terrorist suspect to buy a semiautomatic weapon? This is a matter of national security.
"We also need to make it harder for people to buy powerful assault weapons like the ones that were used in San Bernardino."
Enlists high-tech
The strategy against IS "is designed and supported by our military commanders and counterterrorism experts together with 65 countries that have joined an American-led coalition."
"We constantly examine our strategy to determine within additional steps are needed to get the job done... And that's why I will urge high-tech and law enforcement leaders to make it harder for terrorists to use technology to escape from justice."
Rules out ground war
"We should not be drawn once more into a long and costly ground in Iraq and Syria. That's what groups like ISIL want.
"They know they can't defeat us on the battlefield ... but they also know that if we occupy foreign lands, they can maintain insurgencies for years, killing thousands of our troops and draining our resources, and using our presence to draw new recruits."
