Three of the men accused of plotting the 11 September 2001 attacks on the United States have entered into a pre-trial agreement, the BBC reports.
The news was confirmed by the US Department of Defense.
Khalid Sheikh Mohammed, Walid Muhammad Salih Mubarak Bin Attash, and Mustafa Ahmed Adam al-Hawsawi have been detained at the US Navy base at Guantanamo Bay, Cuba, for years without going to trial.
According to the BBC, details of the deal have not been announced, but US media say the men will plead guilty in exchange for the prosecution agreeing not to seek the death penalty.
Brett Eagleson, the president of 9/11 Justice, an organisation representing survivors and relatives of victims of the 2001 attacks, said in a statement that the families were “deeply troubled by these plea deals”.
Nearly 3,000 people in New York, Virginia and Pennsylvania were killed in the attacks, which sparked the “War on Terror” and the invasions of Afghanistan and Iraq.
The 9/11 attacks were the deadliest assault on US soil since the 1941 Japanese attack on Pearl Harbor, in which 2,400 people were killed.