A federal judge heard arguments Friday on whether to dismiss most of the charges against a suspected Libyan militant accused in the 2012 deadly attacks at the U.S. diplomatic compound in Benghazi, an incident that's become a political flashpoint in the U.S. presidential campaign and remains under investigation by a special House committee.

U.S. District Judge Casey Cooper did not immediately rule on the motions but appeared almost certain to keep the terrorism case against Ahmed Abu Khattala moving toward trial.

Still, it wasn't clear whether all of the counts in the indictment would remain intact, including one charge -- use of a firearm during a crime of violence -- that defense lawyers argued was intended to prosecute domestic, rather than international, crimes. The judge at times appeared receptive to defense arguments of prosecutorial overreach.

Khattala, captured by U.S. special forces in Libya in a nighttime raid in June 2104 and then questioned for days aboard a Navy vessel, appeared in court for the most significant hearing in the case in months. Wearing a green prison suit, he listened silently to the proceedings through earphones as an interpreter translated the arguments.

The September 2012 attacks at the compound in Libya killed Ambassador Chris Stevens and three other Americans, raising questions in Congress and at the State Department about diplomatic security at the post. Hillary Rodham Clinton, who is seeking the Democratic presidential nomination, was secretary of state at the time of the attacks and is expected to appear next week before a House select committee investigating the violence. The panel on Friday questioned one of her longtime aides.

An 18-count indictment charges Khattala with crimes including murder of an internationally protected person, providing material support to terrorists and destroying U.S. property while causing death. He has pleaded not guilty, and prosecutors said Friday that they expect a decision within months on whether the Justice Department would pursue the death penalty.

Defense lawyers laid out multiple challenges to the bulk of the indictment.

Mary Petras, one of Khattala's attorneys, urged Cooper to dismiss the two counts accusing her client of providing support to terrorist groups. Though that statute is a favored prosecution tool, particularly in its cases against U.S. followers of the Islamic State group, Petras said the allegations in the case were unconstitutionally vague about exactly who is a terrorist and what sort of act should be labeled as terrorism.

"Essentially what the government is saying to the court is, `Leave it to us. We know when to use the statute,"' Petras said.

Defense lawyers also asked Cooper to dismiss many other counts, such as carrying and firing a firearm during a crime of violence, that were brought under laws they said were specifically intended by Congress to cover domestic crimes, not ones that occur overseas.

"The court should not stretch the ... presumption that they don't apply to make them apply here," defense lawyer Jeffrey Robinson said.

Though Cooper did not reveal how he would rule, he posed several questions to prosecutors -- including how the government thought it should draw the line on extending its reach into foreign countries -- that suggested that the argument resonated with him.

A separate motion, one that seeks to have Khattala returned to Libya, was not heard on Friday. Defense lawyers have also raised the possibility of filing additional motions once the information-sharing process known as discovery is completed.