NEW YORK - A leading U.S. newspaper reported Sunday the U.S. military has a secret network of private spies still operating in Afghanistan and Pakistan, despite concerns about its legality. The New York Times says the private contractors have become "an important source of intelligence," even though Defense Department rules that prohibit the hiring of contractors for spying. The Times noted the U.S. military is "largely prohibited from operating inside Pakistan." Earlier in the year, U.S. government officials said the network of spies had been shut down, saying it was a rogue operation. The paper said the private spies are being paid under a $22-million contract managed by defence corporation Lockheed Martin and supervised by the Pentagon office in charge of special operations policy. The New York Times says its report about the continuing spy operation is based on interviews with more than a dozen current and former government officials and businessmen, in addition to a number of government documents. Some unnamed Pentagon officials were cited as saying that over time the operation appeared to morph into traditional spying activities. And they pointed out that the supervisor who set up the contractor network, Michael Furlong, was now under investigation. But a review of the programme by The New York Times found that Furlong's operatives were still providing information using the same intelligence gathering methods as before. Geoff Morrell, the Pentagon press secretary, said that the programme "remains under investigation by multiple offices within the defence department," so it would be inappropriate to answer specific questions about who approved the operation or why it continues. "I assure you we are committed to determining if any laws were broken or policies violated," he said. Spokesmen for General David Petraeus, head of the US Central Command, and Gen. Stanley McChrystal, the top American commander in Afghanistan, declined to comment. Furlong remains at his job, working as a senior civilian Air Force official, The Times said. With the wars in Iraq and Afghanistan, the expanded role of contractors on the battlefield - from interrogating prisoners to hunting terrorism suspects - has raised questions about whether the United States has outsourced some of its most secretive and important operations to a private army many fear is largely unaccountable, The Times said. The CIA has relied extensively on contractors in recent years to carry out missions in war zones.