WASHINGTON: An internal Justice Department memo says it is legal for the government to kill US citizens abroad if it believes they are senior Al Qaeda leaders continually engaged in operations aimed at killing Americans.

The document, reported on Monday night by NBC News, provides a legal rationale behind the Obama administration’s use of drone strikes against Al Qaeda suspects.

The 16-page document says it is lawful to target Al Qaeda-linked US citizens if they pose an “imminent” threat of violent attack against Americans, and that delaying action against such people would create an unacceptably high risk. Such circumstances may necessitate expanding the concept of imminent threat, the memo says.

“The threat posed by Al Qaeda and its associated forces demands a broader concept of imminence in judging when a person continually planning terror attacks presents an imminent threat,” the document added.

A September 2011 drone strike in Yemen killed Anwar al-Awlaki and Samir Khan, both US citizens.

The memo does not require the US to have information about a specific imminent attack against the US. But it does require that capture of a terrorist suspect not be feasible and that any such lethal operation by the United States targeting a person comply with fundamental law-of-war principles.

“A decision maker determining whether an Al Qaeda operational leader presents an imminent threat of violent attack against the United States must take into account that certain members of Al Qaeda ... are continually plotting attacks against the United States” and that “Al Qaeda would engage in such attacks regularly to the extent it were able to do so”, says the document.    The document also says that a decision maker must take into account that “the US government may not be aware of all Al Qaeda plots as they are developing and thus cannot be confident that none is about to occur; and that ... the nation may have a limited window of opportunity within which to strike in a manner that both has a high likelihood of success and reduces the probability of American casualties.”

With this understanding, the document added, a high-level official could conclude, for example, that an individual poses an imminent threat of violent attack against the United States where he is an operational leader of Al Qaeda or an associated force and is personally and continually involved in planning terrorist attacks against the United States.

The American Civil Liberties Union, an advocacy group, said the document is “profoundly disturbing”.    “It’s hard to believe that it was produced in a democracy built on a system of checks and balances,” the ACLU said.—AP