Many Islamic leaders say the Fort Hood shooting could pose the sternest test for U.S. Muslims since the Sept. 11 terrorist attacks.

Muslims nationwide are expressing shock, anger and fear that efforts to erase anti-Islamic stereotypes will be eroded in the wake of the shooting.

Maj. Nidal Malik Hasan is accused in the rampage that killed 13 and left him and 29 others wounded.

Hasan is an Army psychiatrist and Muslim who attended his former mosque daily and had an ''Allah is Love'' bumper sticker on his car.

The confirmation of Hasan's faith has prompted major Muslim groups and mosques to condemn the killings and praise the service of Muslim Americans in the U.S. military.

But some Muslims say they are weary of apologizing for others' actions.