Abu Anas Al-Liby, whose real name was Nazih al-Ragye, was seized by the US forces in October 2013 in the Libyan capital Tripoli and was brought to the United States to face criminal charges stemming from the bombings, which killed 224 people.
Al-Liby, 50, died at a local hospital after being transported from a lower Manhattan correctional center on Wednesday, NBC reported, citing court records filed by the Manhattan US Attorney's Office. Reuters could not independently verify the report.
The Attorney's Office could not be reached and the filings could not be immediately located. Al-Liby's attorney, Bernard Kleinman, could also not be immediately reached.
Kleinman told the Washington Post that al-Liby's health had declined rapidly in the past month, though he did not know the cause of death.
Al-Liby's family said he had suffered from the liver disease Hepatitis C, and his health had delayed previous court hearings.
Al-Liby had been scheduled to face trial, along with accused Osama bin Laden associate Khalid al-Fawwaz, on January 12. Both men had pleaded not guilty.