The Army chief of staff says it's important for the country not to get caught up in speculation about the Muslim faith of the alleged Fort Hood gunman.

Gen. George Casey says he's instructed his commanders to be on the lookout for that reaction to the killings at the Texas post.

He says focusing on the Islamic roots of the suspected shooter, Maj. Nidal Malik Hasan (nih-DAHL' mah-LEEK' hah-SAHN'), could "heighten the backlash" against all Muslims in the military.

Casey says diversity in the military "gives us strength."

Casey declined to answer questions about the investigation into the shooting, but said evidence to this point shows that Hasan acted alone. He toured Fort Hood on Friday with Army Secretary John McHugh.

Casey appeared on ABC's "This Week" and CNN's "State of the Union."

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

WASHINGTON (AP) _ The Army chief of staff says it's important for the country not to get caught up in speculation about the Muslim faith of the alleged Fort Hood gunman.

Gen. George Casey says focusing on the Islamic roots of Maj. Nidal Malik Hasan (nih-DAHL' mah-LEEK' hah-SAHN') could "heighten the backlash" against all Muslims in the military.

Casey says diversity in the military "gives us strength."

Casey declined to answer questions on ABC's "This Week" about the investigation into the shooting, but said evidence to this point shows that Hasan acted alone.