The federal arraignment Saturday of the suspected ringleader of the 2012 Benghazi attacks is likely to revive the political firestorm over prosecuting terrorism suspects on American soil.
Libyan militant Ahmed Abu Khatallah, his long, graying hair and beard slightly unkempt, arrived amid heavy security at a U.S. courthouse in Washington, just blocks from the Capitol.
It was his first public appearance since being captured this month in a secret raid near Benghazi, where he had been living freely since the attack on a U.S. compound in the eastern Libyan city.
Dressed in a dark hooded sweat shirt and listening to an Arabic translation of the proceedings, Abu Khatallah pleaded not guilty to a one-count indictment related to his suspected role in the Sept. 11, 2012, attack, which killed four Americans, including Ambassador J. Christopher Stevens.
Prosecutors said they expected to file additional charges, including one that carries the death penalty.
"He will face the full weight of our justice system," Atty. Gen. Eric H. Holder Jr. said in a statement Saturday.
The Obama administration's decision to bring Abu Khatallah to American territory rather than the U.S. military detention facility at Guantanamo Bay, Cuba, is expected to unleash criticism from Republican lawmakers.
Prosecution of a militant like Abu Khatallah in the nation's capital is rare, and critics say bringing such suspects to the U.S. may pose security risks and could allow terrorism suspects to exploit the U.S. justice system.¿
Sens. John McCain (R-Ariz.) and Lindsey Graham (R-S.C.) have raised questions over the decision to hold the suspect in the United States, particularly amid the ongoing investigations in Congress about the administration's handling of the Benghazi attacks.
Sen. Kelly Ayotte (R-N.H.) said Saturday she had "serious concerns" that "turning [Abu] Khatallah over to our civilian courts risks losing critical intelligence that could lead us to other terrorists or prevent future attacks."
The Justice Department has argued that the federal courts have tried hundreds of lower-level terrorism cases, and are capable of handling those of suspected militants.
Holder has previously cited the successful conviction in federal court in Manhattan of Sulaiman abu Ghaith, Osama bin Laden's son-in-law and spokesman, as an example of the civilian court's ability to handle such cases.
President Obama has pledged to shut down the prison at Guantanamo, which critics say violates human rights. Administration officials say they do not want to bring additional detainees to the facility.
Obama had tried to move suspected Sept. 11 mastermind Khalid Shaikh Mohammed and his accomplices from Guantanamo to face trial in federal court in New York, but lawmakers from both parties objected. In 2011, Congress made it illegal to transfer prisoners from Guantanamo to the U.S.
Since Abu Khatallah's capture this month, U.S. officials had been questioning him aboard a Navy amphibious transport.
The Pentagon has called Abu Khatallah a "key figure" in the attack in Benghazi, when militants stormed the compound and overwhelmed Libyan guards.
On Saturday, speaking in Arabic, he only answered "yes" after being sworn in, but appeared to be listening intently as Magistrate Judge John M. Facciola slowly and deliberately explained the case against him and his rights before the court.
Abu Khatallah's federal defender, Michelle Peterson, entered the not-guilty plea on his behalf to the single charge of conspiracy to provide material support to terrorists, which carries a life sentence.
Assistant U.S. Atty. for the District of Columbia Michael DiLorenzo told the court that the government was seeking additional indictments from the grand jury. The government's three-count federal complaint against Abu Khatallah, unsealed at the time of his capture, includes one — causing the death of an American on federal property — that carries the death penalty.
A detention hearing was set for Wednesday.
The State Department designated Abu Khatallah a terrorist in January, describing him as a leader of Ansar al Sharia, a Libyan militant group that has been described as having links to Al Qaeda.
The administration's narrative about events on the night of the attack has fueled harsh criticism, mostly from Republicans, who accused Obama of initially attempting to downplay the terrorist links of those responsible.