President Barack Obama is defending the use of drone strikes against American citizens abroad who the administration believes are a national security threat.

President Barack Obama speaks at the National Defense University (Win McNamee/Getty Images)

In a speech, Obama says when an American goes abroad to wage war against the U.S., his citizenship "should no more serve as a shield" than a sniper shooting on an innocent crowd should be protected from a SWAT team.

Obama's speech comes after mounting pressure from lawmakers in both parties for the administration to explain its guidelines for using drone strikes against U.S. citizens. It also follows the administration's disclosure Wednesday that four Americans had been killed abroad by drone strikes since 2009.

Obama is also renewing renew his call to close the federal detention center in Cuba.

New guidelines in place for drone strikes

Obama says he has signed new policy guidelines to oversee when the U.S. can use drone strikes against suspected terrorists.

Obama says clear guidelines, oversight and accountability are spelled out in "policy guidance" he signed Wednesday.

He says Thursday in a speech that the administration has been working for the past four years to put in place a framework that governs the use of force against terrorists.

Congress briefed on every drone strike

Obama says his administration informs Congress about every drone strike America orders.

In a national security speech Thursday, Obama said the administration has briefed the appropriate congressional committees about all drone strikes outside of Iraq and Afghanistan, such as in Yemen.

He says the briefings included the one instance in which an American citizen was the target: Anwar al-Awlaki. Officials say al-Awlaki was a leader in a branch of al-Qaida that operated in the Arabian peninsula, and that he had ties to at least three attacks planned or carried out on U.S. soil.

Obama spoke a day after the administration disclosed the deaths of three other Americans abroad in drone strikes.

Obama says he authorized the release of the information to encourage debate on the issue.

More oversight of drone strikes

President Barack Obama says his administration is willing to consider accepting increased oversight of lethal drone strikes outside of war zones like Afghanistan.

In a speech on new contours of his counterterrorism strategy, Obama took note Thursday of a number of proposed ways of doing that —- including the establishment of an independent oversight board in the executive branch of the government.

He did not endorse any particular proposal but said he will engage Congress in exploring a number of options for increased oversight. He cautioned that some proposals may introduce a layer of bureaucracy into national-security decision-making, without giving the public added confidence in the oversight process.

Anti-war protester shouts at Obama

Medea Benjamin, an activist from the organization called Code Pink, shouts at President Barack Obama while he speaks at the National Defense University

President Barack Obama was interrupted three times by a woman who shouted about drones and detainees in Cuba as he delivered a speech on national security.

The woman was identified as Medea Benjamin from the anti-war group Code Pink. Benjamin yelled from behind a bank of cameras before security removed her from the hall at National Defense University in Washington.

Obama at one point said he was willing to "cut the young lady some slack" because the issues he was addressing are worth being passionate about.

Benjamin shouted, quote, "86 were cleared already. Release them today!"

That appears to be a reference to detainees who remain in Cuba despite being cleared for transfer from the facility.