The United States' short-term approach in Afghanistan has made stability harder to achieve in the South Asian country, an independent study says.

When U.S. president-elect Barack Obama takes office in under two weeks, he should focus the mission on rebuilding the country and view it as a decade-long project, according to the report by the United States Institute of Peace.

"The refusal by the administration to properly anticipate and plan for the political ramifications of the Afghan and Iraq interventions has made the job that much harder still," wrote J. Alexander Thier, an Afghan scholar at the institute.

The 124-page compilation of essays by Afghan analysts, edited by Thier, was released Thursday for a conference to be attended by Gen. David Petraeus, who is in charge of the Afghan and Iraq wars.

Petraeus is expected to present his own review of U.S. strategy in Afghanistan to Obama the week after the Jan. 20 inauguration. Obama wants the U.S. focus to shift from Iraq to the escalating Afghan conflict.

"The Bush administration has had all but eight months of its entire tenure to stabilize Afghanistan and here it is January," Thier told the Associated Press. "One of the top foreign policy priorities for the Obama administration is to stabilize Afghanistan."

Thier writes that the Bush administration was ill-equipped to take a long-term approach to Afghanistan, and let its own national security concerns largely dictate the mission's direction.

Efforts to set up a legitimate government, including the development of Afghan security forces, were underfunded and poorly orchestrated, the document says.

Instead, the U.S. administration relied heavily on proxy armies of warlords with total disregard for the law, the report says.

Comparing the Afghanistan war to the Vietnam War, Thier says: "Seven years of short-term thinking have gotten us to a place where, out of desperation, we can only think short-term."

Thier says the Afghan invasion became overshadowed by operations in Iraq, a conflict that also harmed U.S. standing in the Islamic world — and adding to its difficulties in Afghanistan.

U.S. plans to send more troops

"What is needed now is a coherent strategy to bridge the gap between conflict and democracy, between burkas and women's equality, between tribal councils and a Supreme Court — the next decade must be about building those bridges," Thier writes.

The U.S. military plans to step up its contribution in Afghanistan, sending at least 20,000 extra troops to the southern region. Some 31,000 U.S. troops are currently in the country.

Those troops will augment the 12,500 NATO soldiers in the region — mainly from Britain, Canada and the Netherlands.

Canada has about 2,500 soldiers stationed in Afghanistan, largely in the volatile Kandahar province.

U.S. military officials hope the influx of troops will help coalition forces hold territories instead of just winning battles.

The United States Institute of Peace is an independent institution funded by Congress and aimed at preventing or resolving violent international conflicts.

With files from the Associated Press