(WASHINGTON) -- One of a handful of Americans who have joined al Qaeda in Pakistan may soon find himself in the crosshairs of a U.S. killer drone, but officials will not say which one. Current and former officials tell ABC News the most likely candidates include fugitive al Qaeda mouthpiece Adam Yahiye Gadahn, and as many as three other American citizens who have taken up arms with al Qaeda in Pakistan or with affiliated groups battling U.S. forces along the border with Afghanistan.
Two unidentified men who each called themselves "Amriki" – "American" in Arabic – appeared several years ago in propaganda videos of an al Qaeda-aligned group in Pakistan. A third American, unnamed by sources but described as a mid-level al Qaeda facilitator in Pakistan, may also be among those possibly eyed for a drone strike for plotting attacks on other Americans.
A top al Qaeda external operations leader also believed to be hiding in Pakistan, Adnan Shukrijumah, grew up in New York and Florida but is a Guyanese citizen and legally only classified as a "U.S. Person."
Since its inception on Sept. 10, 1988, al Qaeda has included Americans in its senior ranks who helped galvanize founder Osama Bin Laden's hard line against the United States as a "crusader" nation bent on oppressing Muslims and lacking the mettle to withstand military challenges to its foreign policy.
Officials confirmed to ABC News that the Obama administration is wrestling over whether to use an armed drone to kill at least one unnamed "American citizen" allegedly aiding al Qaeda in a country which current and former counterterrorism officials said is likely Pakistan, where Bin Laden was killed by U.S. commandos in 2011. Capture by U.S. Special Operations forces would be extremely difficult there.
The White House and Office for the Director of National Intelligence each declined requests for comment by ABC News last week about the targeting of U.S. citizens with al Qaeda and the reported legal debate.
One senior official, who told ABC News that the individual under scrutiny is among a handful of known American "core" al Qaeda senior operatives in Pakistan, Syria, Somalia and possibly Yemen, added that the legalities of whether, how and who would be tasked with the targeted killing of a U.S. citizen posing a direct threat to other Americans have been resolved.
The target list has been fully vetted by administration lawyers, said knowledgeable sources, who believe there is high-level concern in the administration that one of the U.S. citizens may be collaterally killed in a strike primarily targeting a more senior al Qaeda leader. President Obama must approve any action to kill an American but incidental deaths of citizens traveling with al Qaeda targets have occurred three times in the past.
"I think what you've got here really is government acting as judge, jury and executioner – the CIA really acting as judge, jury, and executioner, with really no meaningful accountability either before the killings take place or after," Jameel Jaffer, an American Civil Liberties Union legal director, told ABC News this week.
At the Pentagon late Friday, spokesman Navy Rear Adm. John Kirby wouldn't address the specific issue of targeting American turncoats for drone strikes. But of the general vetting of those the U.S. military takes aim at with drones, Kirby said, "There's a very robust discussion about targeting and who is a legitimate target and who is not."
The U.S. government has killed at least four of its citizens in direct action assaults aimed at al Qaeda in recent years, according to Obama in a speech he gave last May. Only one, al Qaeda in the Arabian Peninsula external operations commander Anwar al-Awlaki, was deliberately targeted, in Yemen, by a drone strike; the others were collateral casualties in strikes targeting other al Qaeda figures.
"For the record, I do not believe it would be constitutional for the government to target and kill any U.S. citizen — with a drone, or with a shotgun — without [constitutional] due process, nor should any President deploy armed drones over U.S. soil," Obama said in the speech last year. "But when a U.S. citizen goes abroad to wage war against America and is actively plotting to kill U.S. citizens, and when neither the United States, nor our partners are in a position to capture him before he carries out a plot, his citizenship should no more serve as a shield than a sniper shooting down on an innocent crowd should be protected from a SWAT team."
Copyright 2014 ABC News Radio