The United States can defeat Al Qaeda if it relies less on force and more on policing and intelligence to root out the terror group's leaders, a new study contends.

"Keep in mind that terrorist groups are not eradicated overnight," said the study by the federally funded Rand research center, an organization that counsels the U.S. Defense Department.

Its report said that the use of military force by the United States or other countries should be reserved for quelling large, well-armed and well-organized insurgencies, and that American officials should stop using the term "war on terror" and replace it with "counterterrorism."

"Terrorists should be perceived and described as criminals, not holy warriors, and our analysis suggests there is no battlefield solution to terrorism," said Seth Jones, the lead author of the study and a Rand political scientist.

"The United States has the necessary instruments to defeat Al Qaeda, it just needs to shift its strategy," Jones said.

Nearly every ally, including Britain and Australia, has stopped using "war on terror" to describe strategy against the group headed by Usama bin Laden and considered responsible for the Sept. 11, 2001 suicide attacks at the World Trade Center in New York and the Pentagon.

Based on an analysis of 648 terrorist groups that existed between 1968 and 2006, the report concluded that a transition to the political process is the most common way such groups end. But the process, found in 43 percent cases examined, is unlikely with Al Qaeda, which has a broad, sweeping agenda, the report said.

The second most common way that terrorist groups end, seen in about 40 percent of the cases, is through police and intelligence services apprehending or killing key leaders, Jones said. Police are particularly effective because their permanent presence in cities helps them gather information, he said.

By contrast, the report said, military force was effective in only 7 percent of the cases.

Jones, in an interview, said, "Even where we found some success against Al Qaeda, in Pakistan and Iraq, the military played a background or surrogate role. The bulk of the action was taken by intelligence, police and, in some cases, local forces."

"We are not saying the military should not play a role," he said. "But unless you are talking about large insurgencies, military force should not be the tip of the spear."

Among the report's conclusions:

—Religious terrorist groups take longer to eliminate than other groups but none has achieved victory in the 38 years covered by the study.

—Terrorist groups from upper-income countries are more likely to be left-wing or nationalist, and much less likely to be motivated by religion.

—Large groups of more than 10,000 have been victorious more than 25 percent of the time, while victory is rare for groups with 1,000 or fewer members.

The report described Al Qaeda as a "strong and competent organization," both before and after the Sept. 11, 2001 terrorist attacks against the United States. Its goals, the report said, are uniting Muslims to fight the United States and its allies, overthrowing regimes in the Middle East friendly to the West and establishing a pan-Islamic state, or caliphate.