Guantanamo detainee Majid Khan formally plead guilty to five war crimes before a military tribunal on Wednesday at the US Navy base at Guantanamo, BBC reported.
The New York Times reported that under the plea deal, Khan will receive a jail sentence of no more than 19 years. He plead guily on several counts, among them assisting Al Qaeda plan attacks from his native Pakistan.
The sentencing, however, has been postponed to 2016, said BBC.
Khan is considered a "high value" detainee by the US, due to his confessed work with Khalid Sheik Mohammed after the 9/11 attacks. He has been in custody for almost nine years, with some of that time spent at the US Guantanamo Bay detention camp in Cuba.
In 2007, Khan testified that he had been "psychologically tortured" and had tried to commit suicide twice, according to BBC.
More from Global Post: Gitmo, the US detention center at Guantanamo Bay, Cuba, turns 10 (VIDEO)
Khan was born in 1980 in Pakistan and moved to the US with his family when he was 16 years old, according to the Washington Post, and reportedly began exploring Islamic extremism following the death of his mother in 2001.
Khan is accused of delivering $50,000 from Al Qaeda to a group that bombed the JW Marriott Hotel in Jakarta and strapping a fake bomb vest to himself in an assassination attempt against former Pakistani President Pervez Musharraf, among other charges.
The US is currently holding 171 prisoners at its detention center at Guantanamo Bay, according to BBC, where they are being tried in closed military courts. Rights groups have raised questions about the grounds of their detainment and criticized the lack of transparency in the legal proceedings.