Three plotters behind 9/11 attacks 'plead guilty to avoid death sentence'

THE US has reached a plea deal with three of the men behind the September 11 attacks, the Pentagon has announced.

- Lydia Chantler-Hicks

Khalid Sheikh Mohammed, the man accused of masterminding the 2001 al Qaeda attacks, and two of his accomplices, held at the US military prison in Guantanamo Bay, Cuba, have all agreed to plead guilty.

A US official said the plea deals almost certainly involved guilty pleas in exchange for taking the death penalty off the table.

Mohammed and his accomplices, Walid Bin Attash and Mustafa al-Hawsawi, are expected to enter the pleas at the military commission at Guantanamo Bay as soon as next week.

Defence lawyers have requested the men receive life sentences in exchange for the guilty pleas, according to letters from the federal government received by relatives of some of the nearly 3,000 people killed on the morning of September 11.