A new Pentagon report to Congress says violence in Afghanistan is on the rise.

The report released Tuesday said the overall security situation has worsened since June, with more effective attacks by insurgents and increased casualties among Afghan security forces.

The report also said the Taliban-led insurgency has been emboldened by the U.S.-led coalition's transition this year from direct combat operations to a train-and-advise role. The U.S. now has about 9,800 troops in Afghanistan.

The report said Afghan forces have demonstrated a will to fight and to learn from their battlefield mistakes. But the Taliban's resilience has made the security situation fragile in key areas and at risk of deteriorating in other places. The Taliban also are effectively exploiting Afghan forces' weaknesses.