The US military since 2004 has used this secret authority to carry out nearly a dozen undisclosed attacks against Al Qaeda. These were authorised by a classified order that Defence Secretary Donald H Rumsfeld signed in the spring of 2004 with the approval of President Bush, the New York Times, quoting the officials, said.

The secret order gave the military new authority to attack the Qaeda terrorist network anywhere in the world, and a more sweeping mandate to conduct operations in countries not at war with the United States, the report said.

In 2006, a Navy Seal team raided a suspected militants' compound in the Bajaur region of Pakistan, the paper said quoting a former top official of the Central Intelligence Agency.

Officials watched the entire mission captured by the video camera of a remotely piloted Predator aircraft  in real time in the CIA's Counter-terrorist Center at the agency's headquarters in Virginia 7,000 miles away, the paper said.

Some of the military missions have been conducted in close coordination with the CIA, American officials told the paper. In others, like the Special Operations raid in Syria on October 26 this year, the military commandos acted in support of CIA-directed operations.

But as many as a dozen additional operations have been cancelled in the past four years, often to the dismay of military commanders, senior military officials told the paper.

They said senior administration officials had decided in these cases that the missions were too risky, were too diplomatically explosive or relied on insufficient evidence.

More than a half-dozen officials, including current and former military and intelligence officials as well as senior Bush administration policy makers, described details of the 2004 military order, the paper said.

Spokesmen for the White House, the Defence Department and the military declined to comment. Apart from the 2006 raid into Pakistan, the paper said the American officials refused to describe in detail what they said had been nearly a dozen previously undisclosed attacks, except to say they had been carried out in Syria, Pakistan and other countries.

They made clear that there had been no raids into Iran using that authority, but they suggested that American forces had carried out reconnaissance missions in Iran using other classified directives, the Times said.

A senior administration official reportedly said the new authority was spelled out in a classified document called 'Al Qaeda Network Exord', or execute order, that streamlined the approval process for the military to act outside officially declared war zones.

Where in the past the Pentagon needed to get approval for missions on a case-by-case basis, which could take days when there were only hours to act.

It also allowed senior officials to think through how the US would respond if a mission went badly. "If that helicopter goes down in Syria en route to a target," the official said, "the American response would not have to be worked out on the fly."

The 2004 order was a step marking the evolution of how the American government sought to kill or capture Qaeda terrorists around the world.

It was issued after the Bush administration had already granted America's intelligence agencies sweeping power to secretly detain and interrogate terrorism suspects in overseas prisons and to conduct warrant-less eavesdropping on telephone and electronic communications.