Baltimore (CNN) -- A Baltimore man arrested Wednesday on charges of plotting to bomb a military recruiting station was alarmed by an FBI sting in Oregon, but stuck with his plan, according to court papers.
Antonio Martinez, 21, was upset by U.S. forces killing Muslims overseas and plotted to blow up the Armed Forces Career Center in the Baltimore suburb of Catonsville, Maryland, according to a federal agent's affidavit. Martinez, a Muslim convert who goes by the name Muhammad Hussain, was arrested Wednesday morning after attempting to detonate an inert device supplied to him by an undercover FBI agent, federal prosecutors announced.
"He stated that because the military in the United States and other countries were fighting against Muslims, soldiers were legitimate targets," according to the affidavit.
But after the November 26 arrest of a Somali-born teenager in the Oregon case, Martinez "expressed concern" about the undercover FBI agent to whom he had been introduced by a government informant, the affidavit states. Martinez told the informant that he needed to know "who this brother is. ... I'm not falling for no b.s," according to the affidavit.
But he decided to go forward with the plot -- and when the undercover agent expressed similar concern two days later, Martinez told the informer, "We have to trust each other. ... We can't stop what we're doing," the affidavit states.
Police "swarmed" a parking lot near the recruiting center when the arrest was made, said Will Eckenrode, a worker at a nearby business.
"We saw the every entrance to the parking lot get blocked by undercover cars as well as Baltimore County police, and we went outside and saw that the FBI in full tactical gear had surrounded the scene," he said.
Martinez is charged with attempting to kill federal officers and attempting to use a weapon of mass destruction against U.S. property. Rod Rosenstein, the U.S. attorney in Baltimore, said Martinez could face up to life in prison if convicted.
The suspect did not enter a plea during a brief court appearance Wednesday afternoon, and he was ordered held until his next hearing, set for December 13.
"It's very, very early in the process, and it's important not to jump to any conclusions," his court-appointed attorney, Joseph Balter, said as he left the courtroom.
Rosenstein said there was no evidence that Martinez "was acting as a part of any larger group."
"I think it's significant that there are four civilians who were contacted by the defendant," he said. "Two of them turned him down, one of them tried to talk him out of it and the third turned him into the FBI."
Wednesday's arrest comes after a string of unsuccessful terror attempts, such as last year's alleged Christmas Day bombing attempt, the botched Times Square car bombing, and the Oregon case, in which federal prosecutors say the suspect attempted to blow up a Christmas tree-lighting in Portland.
"More and more individuals in the United States are themselves becoming radicalized to the point of violence,"
Homeland Security Secretary Janet Napolitano said. "And that's what we're focused on."
Marcia Murphy, a spokeswoman for the U.S. attorney's office in Baltimore, said there was no evidence tying the suspect to a string of recent shootings at other recruiting centers in the metropolitan Washington area.
In court papers, federal agents state that Martinez "struck up an association" with the FBI informant in October after posting a late September message on Facebook that vowed, "The sword is cumming (sic) the reign of oppression is about 2 cease."
The informant contacted Martinez over Facebook, and Martinez told him "that he wanted to go to Pakistan or Afghanistan (a country that struggle for the sake of Allah)," according to the affidavit. But later, Martinez began talking about attacking a military recruiting center, according to the affidavit.
"He indicated that if the military continued to kill their Muslim brothers and sisters, they would need to expand their operation by killing U.S. Army personnel where they live. He stated that jihad is not only in Afghanistan or Pakistan, but also in the United States," the affidavit sates.
The informer offered to introduce Martinez to an "Afghani brother" -- actually an undercover FBI agent -- who could help, according to the affidavit.
According to the affidavit, Martinez wanted to send a message that anyone who joins the U.S. military "will be killed," and hoped to organize a Muslim uprising against U.S. forces inside the country, the affidavit states. He attempted to detonate the fake bomb outside the recruiting center after the undercover agent reported seeing soldiers inside, the affidavit states.
The undercover agent told the suspect several times that he didn't have to go forward with the plan, but Martinez decided to stick with it, according to the affidavit.
At the White House, spokesman Nick Shapiro said President Barack Obama had been notified of the operation before Wednesday's arrest. Obama "was assured that the FBI was in full control of the operation and that the public was not endangered," Shapiro said.
The case bears similarities to the Oregon one because of the sting techniques used, the source said.
Oregon State University student Mohamed Osman Mohamud, 19, was arrested after prosecutors said he attempted to detonate what he thought was an explosives-laden van parked near a tree-lighting ceremony at Portland's Pioneer Courthouse Square. The Justice Department said Mohamud's arrest came after a long-term undercover operation during which the teen was monitored closely.
Mohamud, a naturalized U.S. citizen from Somalia, has pleaded not guilty to a single count of attempting to use a weapon of mass destruction. A trial date has been set for February 1.
Mohamud's lawyer, Stephen Sady, has said government agents entrapped his client, "grooming" him as a potential bomber and providing him with money and transportation to support the plot. But Rosenstein said federal agents are "not in the business of entrapping people."
"First of all, they don't initiate these investigations unless there is a credible allegation that the defendant himself is already expressed an intent to cause harm," Rosenstein said. "And secondly, throughout the investigation, the FBI seeks to clarify the defendant's intent, challenging him, making certain that he's expressly told that he doesn't need to go forward with this."
And while Napolitano declined to discuss the Baltimore arrest specifically, she said stings "are part and parcel of the toolbox law enforcement must have and must employ, particularly in this type of terrorist environment."
CNN's Larry Lazo, Carol Cratty, Mike Ahlers and Jeanne Meserve contributed to this report.