The United States says Afghan soldiers and police are sustaining the gains made by NATO forces during a troop surge two years ago, but they will require more support to be successful in the long run.

That is the view of U.S. Defense Secretary Chuck Hagel in a report to the U.S. Congress Friday. When the NATO mission in Afghanistan concludes at the end of 2014, he says, Afghan forces "will be at high risk" unless they receive continued aid and advice from the international community and the international coalition.

His report says there has been a fundamental shift in the fighting in Afghanistan, with Afghan forces now handling 95 percent of conventional operations and 98 percent of special operations.

It says the fact that Afghan forces are holding their own is a major is a major accomplishment. It notes they are now able to defend gains made by a coalition of 50 nations with the "best trained and equipped forces in the world."

According to the report, there has been a six percent dip in enemy-initiated attacks compared with last year. Security incidents are down by 12 percent and roadside bombings by 22 percent.

The report says casualties to Afghan forces are up 79 percent compared with last year, while those for the NATO-led coalition have dropped 59 percent.

U.S.-led foreign troops have been reducing their presence in Afghanistan in preparation for a full withdrawal by the end of next year.