This image made available by Al-Jazeera shows Sulaiman Abu Ghaith, Osama bin Laden's son-in-law and spokesman. Abu Ghaith has been captured by the United States, officials said Thursday, March 7, 2013, in what a senior congressman called a "very significant victory" in the fight against al-Qaida. AP Photo/Al-Jazeera A Homeland Security vehicle sits in front of a federal court in New York on March 8, 2013, where Sulaiman Abu Ghaithwhere, a senior al-Qaida leader and son-in-law of Osama bin Laden, pleaded not guilty to plotting against Americans in his role as the terror network's top spokesman. The case marks a legal victory for the Obama administration, which has long sought to charge senior al-Qaida suspects in U.S. federal courts instead of holding them at the military detention center at Guantanamo Bay, Cuba. Charging foreign terror suspects in federal courts was a top pledge by President Barack Obama shortly after he took office in 2009, aimed, in part, to close Guantanamo Bay. AP Photo/Peter Morgan NEW YORK (AP) - A senior al-Qaida leader and son-in-law of Osama bin Laden, captured in Jordan a week ago, pleaded not guilty Friday in a heavily secured New York courtroom to plotting against Americans before and immediately after the Sept. 11 attacks in his role as the terror network's top spokesman. Bearded and balding, Sulaiman Abu Ghaith was escorted into the largest courtroom at the federal courthouse in Manhattan, where he entered the plea through a lawyer to one count of conspiracy to kill Americans in a case that marks a legal victory for President Barack Obama's administration. Assistant U.S. Attorney John P. Cronan revealed that Abu Ghaith gave an "extensive post-arrest statement" that totaled 22 pages after he was arrested overseas the night of Feb. 28 and arrived in the U.S. March 1. The prosecutor said nothing about the contents of Abu Ghaith's statement. A law enforcement official with knowledge of the case said Abu Ghaith initially agreed to be interviewed without an attorney at the FBI office in lower Manhattan immediately after his arrival. Later in the day, he requested an attorney and was interviewed with an attorney present. The official spoke on condition of anonymity because he was not authorized to talk about the case. Nearly a dozen deputy U.S. marshals guarded the ceremonial courtroom as about 80 spectators, mostly journalists, lawyers and court employees, watched the 15-minute proceeding before U.S. District Judge Lewis A. Kaplan, a no-nonsense judge who promised to set a trial date when Abu Ghaith returns to court on April 8. Black cuffs that bound his hands behind him were taken off Abu Ghaith after he sat next to his court-appointed federal defender, Philip Weinstein. His prison blue uniform covered a brown shirt. The judge told him he could remain seated. Kaplan read him the charges he faced, including passages describing how Abu Ghaith appeared with bin Laden and current al-Qaida leader Ayman al-Zawahri the day after the Sept. 11 attacks and said a "great army is gathering against you" as he called on the "nation of Islam" to battle against Jews, Christians and Americans. Then, the judge said, Abu Ghaith shortly afterward warned in a speech that "the storms shall not stop - especially the airplanes storm" and advised Muslims, children and al-Qaida allies to stay out of planes and high-rise buildings. Kaplan advised Abu Ghaith: "This is not a trial." He then read him his rights. Through an interpreter, Kaplan asked whether Abu Ghaith understood his rights. Abu Ghaith nodded and said, "Yes, I do." Asked whether he had money to hire an attorney, Abu Ghaith shook his head and said no. He nodded and said yes when asked whether he had signed an affidavit describing his financial situation. Bail was not requested, and none was set. Prosecutors said a trial would last about three weeks. After the proceeding, Abu Ghaith's lawyer declined comment. The Obama administration has long sought to charge senior al-Qaida suspects in American federal courts instead of military tribunals at the detention center at Guantanamo Bay, Cuba. But it runs counter to demands by Republicans in Congress who do not want high-threat terror suspects brought into the United States. Abu Ghaith was born in Kuwait and was bin Laden's son-in-law. The Department of Justice said he was the spokesman for al-Qaida, working alongside bin Laden and al-Zawahri, since at least May 2001. Abu Ghaith is a former mosque preacher and teacher. Kuwait stripped him of his citizenship after Sept. In 2002, under pressure as the U.S. military and CIA searched for bin Laden, Abu Ghaith was smuggled into Iran from Afghanistan, prosecutors said. Charging foreign terror suspects in American federal courts was a top pledge by Obama shortly after he took office in 2009, aimed, in part, to close Guantanamo Bay. Several GOP lawmakers on Thursday said Abu Ghaith should be considered an enemy combatant and sent to Guantanamo. Associated Press writers Lara Jakes in Washington and Jamal Halaby in Amman, Jordan, contributed to this report.