The CIA and the military special forces have quietly expanded the role of private contractors, including Blackwater, to include their involvement in raids and secret paramilitary operations in Afghanistan, Pakistan and Iraq, four current and former U.S. military and intelligence officers tell ABC News.
American law specifically prohibits the use of private soldiers or mercenaries in combat, according to Jonathan Turley, a professor of public interest law at George Washington University.
"The United States Congress has never approved the use of private contractors for combat operations," Turley told ABC News in an interview to be broadcast tonight on ABC World News with Charles Gibson.
CIA officials acknowledge that two private contractors were killed in Afghanistan in 2003 when they and other members of a CIA paramilitary team were in a firefight with Taliban fighters on a remote road.
In another case, in 2006, 12 Blackwater "tactical action operatives" were recruited for a secret raid into Pakistan by the U.S. military's Joint Special Operations Command, according to a military intelligence planner. The target of the planned raid, code-named Vibrant Fury, was a suspected al Qaeda training camp, according to the planner, who said he did not know the outcome of the mission.
In Iraq, a high-ranking U.S. Army officer told ABC News, Blackwater personnel have been used in military operations that "are supposed to include U.S. soldiers but often end up with the Blackwater people on their own."
The New York Times reported Friday that such raids against Iraqi insurgents were conducted "almost nightly" between 2004 and 2006, and it quoted several Blackwater guards as saying "the operations became so routine that the lines supposedly dividing the Central Intelligence Agency, the military and Blackwater became blurred."
The Washington Post today quoted former government officials as saying Blackwater's actions included "active participation in raids overseen by CIA or special forces personnel."
American officials reject the term "mercenary," but others say the term applies if the role of private American contractors has been so significantly expanded beyond their previously known assignments in security and logistics.
"If contractors have been sent on true combat missions, missions where they are supposed to kill and engage the enemy, then they are by every definition of the term mercenaries," said Professor Turley.
"To have such a force without allowing Congress to approve it would be considered a very serious offense to our Constitution," said Turley.
A CIA spokesperson, George Little, acknowledged the use of contractors "in roles that complement and enhance the skills of our workforce, just as American law permits."
Little said "it's the way things actually work in the real world," and he stressed that CIA officials always retained "decision-making authority and bear responsibility for results."
"CIA does not use Blackwater to perform our core missions of collecting intelligence, performing analysis or conducting covert operations," said Little.
A U.S. government official told ABC News the private contractors "don't kick down doors" but only fulfill a "security role" on certain CIA missions.
The new CIA director under the Obama administration, Leon Panetta, has continued a "rigorous look" at the use of contractors and a "thorough review" of Blackwater's contracts.