Although the research aimed at tracking and disabling drones is at an early stage, there has been at least one field test, according to sources.
An independent report commissioned by the American Psychological Association found that some of its senior officials helped justify "enhanced interrogation."
The Defense Department's research arm says the need for new weaponry is "critical."
The United States has indications that Iran has carried out air strikes on Islamic State targets in Iraq in recent days, U.S. officials said on Wednesday.
Ashton Carter is a former deputy secretary at the Department of Defense.