The New York Times reported on Wednesday that the man accused of plotting the Sept. 11, 2001 attacks, Khalid Sheikh Mohammed, and two of his accomplices held at the Guantanamo prison have agreed to plead guilty to conspiracy charges in exchange for a life sentence.

The deal for the guilty pleas by Mohammed, Walid Bin Attash and Mustafa al-Hawasawi rather than a death penalty trial has been approved by a senior Pentagon official, according to the report.

The Department of Defense later confirmed that prosecutors have agreed to plea agreements with the three, but did not disclose the terms and conditions of the plea deals.

All three men have been in custody since 2003. Mohammed is an Al-Qaeda terrorist accused by the US of being the principal architect of the Sept. 11 attacks on New York's World Trade Center and the Pentagon. He and four others were charged in 2012 with terrorism, hijacking aircraft, conspiracy, murder in violation of the law of war, attacking civilians, attacking civilian objects, intentionally causing serious bodily injury, and destruction of property in violation of the law of war.

"In exchange for the removal of the death penalty as a possible punishment, these three accused have agreed to plead guilty to all of the charged offenses, including the murder of the 2,976 people listed in the charge sheet," the chief prosecutor, Rear Admiral Aaron Rugh, said in a letter to family members of Sept. 11 victims, according to the Times.

The letter said the men could submit their pleas in open court as early as next week.