WASHINGTON — Violence in Afghanistan is up nearly 90 percent from this time last year, according to a new Pentagon report submitted to Congress Wednesday.

Despite that increase and a 240 percent spike in roadside bomb attacks - a major factor in overall violence statistics - and increasing Taliban tactics to discredit President Hamid Karzai's government with shadow governments, some officials said they are seeing encouraging trends.

"We have the beginnings of the potential for real change," said a senior U.S. defense official who is closely involved with the Obama administration's Afghanistan strategy. The additional troops ordered by President Barack Obama, the official said, "have begun to have some impact on reducing the Taliban's ability to operate."

The new report tracks progress in Afghanistan from October 2009 to March 2010, revealing that an overall decline in stability over the last several years appears now to have steadied. But overall violence has risen, mostly due to an increase in allied offensives reaching into Taliban-controlled areas, as well as successful Taliban efforts to return to areas that had been cleared by U.S. troops.

The United States faces two major concerns in Afghanistan, the senior defense official said: developing Afghan security forces and stopping corruption.

A recent poll indicated that more than 80 percent of Afghans are affected by government corruption in their daily lives. About a third believe the government is less corrupt than a year ago, but a near equal number believes it is more corrupt.

Progress is slow. The government was to have enacted 13 new anti-corruption measures by the end of February, but as of last month, only one of the decrees had been signed, the Pentagon report said.

"Public perceptions of the government with regard to corruption continue to be decidedly negative, with blame placed on ISAF and the rest of the international community as well as the government," the report says. ISAF is the NATO-led International Security Assistance Force.

There have been some recent acts aimed at cleaning up corruption, the defense official said, citing an Afghan police general who was convicted of stealing from a "widows and orphans" fund. But overall, eliminating corruption is "elusive now. It was elusive two years ago. And it was elusive five years ago."

The official said building Afghan security forces is both challenging and risky.

"There is significant risk to us attaining our goals," the officials said. "There is a lot of concern over the ability of the Afghan National Police to grow."

The report describes problems inside the force with individuals not on the payroll doing police work in some districts, as well as "ghost police" who are on the payroll but don't actually show up for duty. The entire police force has begun to be drug tested, and the most recent results found nearly 14 percent of the force tested positive.

The report also details a severe shortage of trainers to build the Afghan forces to sufficient size and quality. But, the senior defense official said, there's been some progress on that front within the last month.

"Since the report closed, we've had more commitments of trainers," the official said. "It's 20 to 30 percent better since the report closed."

The report also indicated that the recent capture of some Taliban leaders over the border in Pakistan has been demoralizing to some Afghan Taliban fighters. The fighters are under more pressure than ever, the report says, but they are still able to get money for their fight from Islamic states outside Afghanistan.

Iran, the senior defense official said, has been "a mixed bag."

"They're doing some positive things in Afghanistan, and some very negative things."