Police say a U.S. soldier arrested after bomb-making material was found in a motel room in the state of Texas planned to target military personnel.

A local police chief, Dennis Baldwin, said Thursday the suspect seemed close to carrying out an attack on Fort Hood, a U.S. Army base in the state. Baldwin described it as a “terror plot.”

Authorities said the soldier, 21-year-old Nasser Jason Abdo, appeared to be acting alone.

Federal charges are expected to be filed against him.

Abdo was arrested on Wednesday in Killeen, Texas, after authorities received a tip about possible bomb-making material in his motel room near Fort Hood. The FBI said agents found weapons and smokeless gunpowder in the room, but that he was being held on unrelated child pornography charges.

Officials said Abdo disappeared from his assigned base, Fort Campbell, in the eastern state of Kentucky, on July 4.

Fort Hood was the scene of a deadly shooting in November 2009 that killed 13 people and wounded 32 others.

A U.S. Army psychiatrist, Major Nidal Hasan, is standing trial in military court for the incident and faces the death penalty if convicted.

U.S. officials have linked Hasan to a radical Muslim cleric in Yemen. Hasan was paralyzed from the waist down after being shot by police on the day of the rampage and remains in jail.

The U.S. Army had granted Abdo conscientious objector status to the wars in Afghanistan and Iraq in June, but that designation had been put on hold following the child pornography charges.