The accused mastermind of the September 11, 2001 terrorist attacks and four other detainees will formally be read the charges against them May 5 in a hearing at the US facility at Guantanamo Bay, Cuba, dpa reported.
The hearing before a military commission moves the men one step closer to trial.
Khalid Sheikh Mohammed, his nephew Ali Abdul Aziz Ali, Walid Muhammad Salih Mubarak Bin 'Attash, Ramzi Binalshibh and Mustafa Ahmed Adam al-Hawsawi could face the death penalty on a series of terrorism charges.
Mohammed was a key al-Qaeda leader when he was captured in Pakistan in 2003 and transferred to US custody.
The charges against them include conspiracy, murder, hijacking, terrorism, attacking civilians, attacking civilian objects, intentionally causing serious bodily injury and destruction of property, the Pentagon said. The attacks killed nearly 3,000 people.
Charges were originally brought against the five suspects during the administration of former president George W Bush, but were dropped after President Barack Obama took office. The Obama administration wanted to transfer the case to civilian courts as part of the effort to close Guantanamo, but relented after running into strong congressional opposition.