KILLEEN, Texas — An AWOL soldier who had weapons stashed in a motel room near Fort Hood admitted to planning an attack on the Texas post, where 13 people died in 2009 in the worst mass shooting ever on a U.S. military installation, the Army said in an alert issued Thursday.

Pfc. Naser Abdo, a 21-year-old soldier who was granted conscientious objector status this year after he said his Muslim beliefs prevented him from fighting, was arrested Wednesday. Agents found firearms and “items that could be identified as bomb-making components, including gunpowder,” in his motel room, according to FBI spokesman Erik Vasys.

The Army alert sent via e-mail says the man arrested by Killeen police “was in possession of a large quantity of ammunition, weapons and a bomb inside a backpack.” Upon questioning, the alert says, he admitted to planning an attack on Fort Hood.

Officials have not offered details about Abdo’s intentions. The infantry soldier from Garland, Texas, had applied for conscientious objector status last year. A military review board recommended this spring that he be separated from the Army.

But the discharge was delayed after he was charged with possessing child pornography and a military hearing last month recommended he be court-martialed. He’s been absent without leave from Fort Campbell, Ky., since the July 4 weekend.