Dallas, Texas (CNN) -- A terrorist suspect accused of two counts of plotting to bomb a skyscraper in Dallas, Texas, pleaded not guilty Monday in federal court.
Hosam Maher Husein Smadi, a 19-year-old Jordanian, entered the United States illegally and lived in Texas, where he tried to set off an explosive attached to a vehicle at the base of the 60-story Fountain Place office tower, federal officials contend.
Smadi initially drew authorities' scrutiny because of his violent posts on an extremist chat site, court papers say. He was arrested last month in a sting operation.
"Smadi was discovered by the FBI within an online group of extremists," the affidavit says. "Among many others in the group who espoused and endorsed violence, Smadi stood out based on his vehement intention to actually conduct terror attacks in the United States."
Undercover officers posing as members of an al Qaeda sleeper cell contacted Smadi and, after months of conversations, considered him to be a legitimate threat, according to the affidavit.
Smadi picked several potential targets, including the Dallas/Forth Worth International Airport, before deciding on the skyscraper, which houses Wells Fargo Bank, the affidavit says.
It details a conversation that Smadi had with authorities in which he allegedly said: "I have decided to change the target. God willing, the strike will be certain and strong. It will shake the currently weak economy in the state and the American nation, because this bank is one of the largest banks in the city."
Smadi said many times that he wanted to commit violent jihad and that he was a soldier of Osama bin Laden, the affidavit says.
Undercover agents tried to get Smadi to "re-evaluate his interpretation of jihad," saying there were nonviolent ways to commit the act, the affidavit says, but "Smadi again communicated his continuing commitment for violent jihad."
After casing the bank in July, Smadi told an undercover agent he would target it, according to authorities. Initially, Smadi told the agent he wanted to bomb the bank on September 11, but decided to wait until the Islamic holy month of Ramadan ended on September 20, authorities said.
After receiving what he thought was an explosive from an undercover agent, Smadi drove a car carrying the fake bomb into a parking garage under the skyscraper, authorities said. Smadi thought he could detonate the bomb by dialing his cell phone.
When he dialed, the number rang a phone in authorities' possession, the affidavit says.
Smadi is charged with attempting to use a weapon of mass destruction, which carries a potential sentence of life in prison and a $250,000 fine upon conviction.
Authorities said they have found no tie between Smadi and any terrorist group.
CNN's Ed Lavandera contributed to this story.