Attorney General Eric Holder in a speech Monday is expected to outline the legal justification for using deadly force in the targeted killings of U.S. citizens overseas, the Associated Press reported.

A senior official in President Barack Obama's administration told the AP that Holder plans to tell an audience at Northwestern University law school in Chicago that using lethal force against al Qaeda cleric Anwar al-Awlaki in Yemen five months ago is legal under a Sept. 18, 2001, joint congressional resolution. Under the Authorization for Use of Military Force, adopted a week after the 9/11 terrorist attacks, the president has the power to authorize the use of all necessary force to prevent any future acts of terrorism against the United States.

In recent months the administration has reportedly engaged in an internal debate over how much information to release about the legal justification of the al-Awlaki assassination. The American-born Muslim cleric was primarily raised in Yemen, although he returned to the United States to attend Colorado State University in the early 1990s.

U.S. officials have claimed al-Awlaki was a senior al Qaeda recruiter and operative who reportedly orchestrated the attempted bombing of an international flight as it approached Detroit on Christmas Day 2009. The Justice Department reported that the Nigerian man apprehended at the scene said his mission was approved after a three-day visit with al-Awlaki.

Obama approved al-Awlaki's targeted killing in December 2010.  U.S. forces deployed an unmanned drone aircraft in Yemen to search for and assassinate the target. Two weeks later, al-Awlaki's 16-year-old son, Abdulrahman al-Awlaki, also a U.S. citizen, was killed in a separate drone strike in the area.

The unprecedented assassinations of U.S. citizens by their own government has been publicly condemned by al-Awlaki's father and challenged in at least three recently civil-rights lawsuits requesting that the administration release its legal justification for the drone strike. The justification is reportedly contained in a classified Justice Department memo.

Holder on Monday will also discuss how the White House revised military commissions and how both the Obama and George W. Bush administrations successfully used civilian courts to convict and sentence terrorists, according to the official who spoke to the AP on condition of anonymity.