By Missy Ryan
WASHINGTON (Reuters) - The U.S. military presented a mixed picture of the war in Afghanistan on Tuesday, saying President Barack Obama's surge of 33,000 extra troops had weakened the Taliban but that a resilient insurgency, persistent corruption, and selective cooperation from Pakistan posed a major threat to U.S. efforts.
In a twice-annual report to Congress, the Defense Department said overall insurgent attacks declined in 2011 for the first time in five years, even though violence increased in areas surrounding the Taliban's southern stronghold of Kandahar, a region where U.S. efforts have been focused since 2009.
Overall, the Pentagon said, violence in Afghanistan decreased by 9 percent in 2011 compared to 2010.
The military statistics, released selectively, showed the United States moving "from us essentially losing the war to us making important progress" and seeking to consolidate those gains as foreign troops withdraw, a senior Defense Department official told reporters.
Yet the report said that "long-term and acute challenges" remain in Afghanistan, including insurgents' ability to renew their fighting power in Pakistan's tribal areas and the "limited capacity" of Afghan President Hamid Karzai's government.
The report's conclusions are unlikely to extinguish doubts about whether the Obama administration can establish a stable, secure Afghanistan as Western nations press ahead with plans to withdraw most combat soldiers by the end of 2014.
The U.S. official, speaking on condition of anonymity, said the evolving state of the Taliban, al Qaeda, and other militants would be clearer this fall, after the summer fighting season.
The Obama administration is due to pull the last of its 33,000 surge troops from Afghanistan by this fall, leaving around 68,000 U.S. soldiers there.
More than 10 years after the Taliban government was toppled, the Afghan insurgency remains "a resilient and determined enemy," the Pentagon said, likely to use high-profile attacks like the 18-hour siege of Kabul on April 15 to shake public confidence.
As the NATO force grows smaller, the Western strategy now hinges on its ability to transform an inexperienced, ill-equipped Afghan army into a professional fighting force that can face off against insurgents alone.
MINIMAL WESTERN SUPPORT
The Defense Department reported that more Afghan police units were considered capable of operating with minimal Western support, even though local forces remain hindered by attrition, poor leadership and inadequate management.
While overall violence declined, the Pentagon said the fight remains intense in the key provinces of Helmand and Kandahar, where thousands of U.S. soldiers have sought to shut down Taliban operations since 2010.
Attacks increased by 13 percent in Regional Command-South, which includes Kandahar, from October 2011 to the end of March 2012 compared to the same period a year earlier. Violence decreased by 29 percent in the area including Helmand during that period.
The report also noted that the share of overall violence has grown in eastern Afghanistan, a base for militants from the Haqqani network whose sophisticated attacks on Western targets may reflect a shift in militant strategy.
The overall number of insurgent attacks in the Regional Command-East area, along the poorly controlled border with Pakistan, declined by 8 percent from October 2011 to the end of March 2012 compared to the same period a year earlier. Overall in 2011, violence there increased 19 percent from 2010.
The Pentagon said that the more recent encouraging trend in eastern Afghanistan and in Kabul may have been aided by an unusually harsh winter.
A year after leader Osama bin Laden was killed in a unilateral U.S. raid in Pakistan, the Pentagon said al Qaeda had been "degraded," but the group retains a small presence in Afghanistan's Kunar and Nuristan provinces.
The Obama administration also continues to grapple with what the Pentagon described as "selective counterinsurgency operations" by the Pakistani government, which U.S. officials have long complained refuses to help the United States hunt down Taliban militants whose interests may align with its own.
Pakistan's decision to keep key supply routes into Afghanistan closed since Pakistani soldiers were killed by U.S. aircraft in November have held up thousands of tons of equipment, the Pentagon said, and could "significantly degrade" withdrawal operations.
(Editing by Vicki Allen)