(Adds comment from lawyer, paragraph 3)
By Jonathan Stempel
NEW YORK, Dec 20 (Reuters) - U.S. prosecutors on Friday added two charges to an indictment accusing Suleiman Abu Ghaith, a son-in-law of Osama bin Laden who once served as a spokesman for al Qaeda, of conspiring to kill Americans.
According to a superseding indictment filed with the U.S. District Court in Manhattan, Abu Ghaith now also faces charges of providing material support and resources to terrorists, and conspiracy to provide such support and resources.
Stanley Cohen, a lawyer for Abu Ghaith, declined immediate comment, saying he had yet to review the indictment.
The indictment adds details of alleged "overt acts," including participation in a propaganda video around Nov. 9, 2001, in which he, bin Laden and others are said to have discussed the upcoming attacks.
It also referred to a speech in which Abu Ghaith allegedly praised an April 11, 2002, suicide bombing of a synagogue in Djerba, Tunisia, and said "we were also granted victory when the world saw with its very own eyes what the Mujahidin did for the sake of God the Almighty in New York and Washington."
Abu Ghaith also then spoke of planning to target American and Jewish interests "inside and abroad," and said "we shall be launching terrorist attacks on America ... at a time, place, and a method of our choosing," according to the indictment.
The Sept. 11 attackers flew two hijacked planes into the World Trade Center in New York and a third one into the Pentagon outside Washington. A fourth hijacked plane crashed in a Pennsylvania field after passengers revolted. Nearly 3,000 people were killed.
U.S. forces in Pakistan killed bin Laden, who masterminded the attacks, in May 2011.
On Nov. 26, Abu Ghaith failed to win the suppression of statements he had made while being interrogated by FBI agents as he was being flown to the United States to face the original indictment. He also failed to have the case dismissed.
Abu Ghaith's trial is scheduled for Feb. 3, 2014, said a spokeswoman for U.S. Attorney Preet Bharara in Manhattan.
Separately, federal prosecutors had on Wednesday indicted Cohen for allegedly failing to report more than $3 million of income to the Internal Revenue Service. Cohen has said he was "fully confident" that he would be vindicated.
The case is U.S. v. Abu Ghayth, U.S. District Court, Southern District of New York, No. 98-cr-01023. (Reporting by Jonathan Stempel in New York, additional reporting by Joseph Ax and Bernard Vaughan; Editing by David Gregorio and Ken Wills)