Officials also said the two ex-convicts behind the plan were hoping to get attention from the media with their plot and even imagined headlines.
Detention hearings are scheduled next week for Abu Khalid Abdul-Latif, also known as Joseph Anthony Davis, 33, of Seattle, and Walli Mujahidh, also known as Frederick Domingue Jr., 32, of Los Angeles.
The men were arrested Wednesday night when they showed up at a warehouse garage to pick up machine guns they planned to use in the attack, authorities said. The weapons had been rendered inoperable by federal agents and posed no risk to the public.
Authorities believe the two men were planning an attack similar to the Fort Hood massacre. They were going to use machine guns and grenades to try and kill everyone in sight.
Authorities said the intended target was a military processing center. News of the plot surprised the roughly 900 people who work in the facility. There's also a daycare near the center.
"That's kind of scary. But you know, I feel pretty secure in the facility," said employee Avril Jones.
Col. Anthony Wright of the Army Corps of Engineers is the highest ranking official in the building. For the last week, he's been in touch with the FBI about the investigation and ordered security changes.
"I don't want to go into specifics of how we respond to those threats, but we do some changes that we believe makes the environment more unpredictable and also improves the security of people in the building," said Wright.
The two suspects claim to be from the Southern California area and both are Muslim converts. Authorities were tipped off by someone the men tried to recruit. He helped render the weapons inoperable.
The wife of Abdul Latif said authorities didn't find anything in her home.
"They told me they are looking for weapon, and I told them we don't have weapon. In the search, they didn't have any weapon in my house," said Binta Moussa-Davis.
The FBI informant claims the suspects were impressed by the 2009 massacre at Fort Hood, Texas, which claimed 13 lives, and were angry with a case in Washington State where five soldiers are charged with killing three Afghan civilians for sport.
This case marks the eighth time in the past two years that attacks have been planned or carried out against military installations in the United States.
The Associated Press contributed to this report.