The New Jersey men -- Mohamed Mahmood Alessa, 20, of North Bergen and Carlos Eduardo Almonte, 24, -- have been charged with conspiring to kill, kidnap or maim persons outside the United States.
If convicted, they could be in prison for life. The two men were arrested at the John F Kennedy airport in New York last Saturday, before they could board separate flights to Egypt on their way to Somalia to join Islamist group Al Shabaab, which controls large parts of the country and is fighting against the Western-backed Transitional Federal Government.
While denying bail, Magistrate Madeline Cox Arleo at the Newark District Court noted that charges levied against the men were severe and there was a risk that two men may try escape.
Both men were dressed in blue jumpsuits and Alessa could be seen smiling several times during the hearing. Almonte's father, a Dominican immigrant, has said that he will not be supporting his son.
Carlos reportedly converted to radical Islam and changed his name to Omar after high school when he stared hanging out with Alessa. Alessa, who is of Palestinian descent, was reportedly a dangerous teen who was kicked out of his high school in North Bergen New Jersey.
The criminal complaint states that the two American citizens prepared for their mission by working out in the gym, doing test runs at paintball fields, saving thousands of dollars, buying cargo pants, listening to videos especially the ones by radical American-Yemeni cleric Anwar Al Awalaki, and reading documents authored by Osama bin Laden and Ayman Al-Zawahiri.
The two were arrested after an undercover agent infiltrated their circle and unearthed their plans. Federal undercover agents secretly recorded the duo making statements to promote violent Jihad.
"We'll start doing killing here, if I can't do it over there," Almonte allegedly said in November 2009, according to the criminal complaint.
Their arrest comes on the heels of a chain of failed attacks on US soil, including a botched car bombing of the Times Square by Pakistani born American Faisal Shahzad on May 1 and the failed Christmas Day bombing of an airliner over Detroit by a Nigerian.
Another Pakistan-American and a former college student from Brooklyn, Syed Hashmi, received 15 years in prison for aiding Al Qaeda in a Manhattan Court this week.