Bradley Manning, the soldier convicted of giving classified US files to WikiLeaks, will be told at 10 am EDT (1400 GMT) on Wednesday how much of his life will be spent in a military prison, a US Army spokesman said on Tuesday.
The judge, Colonel Denise Lind, began deliberating Manning's sentence on Tuesday and later told the court that sentencing would take place at 10 a.m., the spokesman said.
Manning, a 25-year-old private first class, could face as up to 90 years in prison for giving more than 700,000 classified files, battlefield videos and diplomatic cables to the pro-transparency website. Prosecutors asked for 60 years, while the defense asked the judge not to rob him of his youth.
Manning, who was a low-level intelligence analyst in Baghdad in 2010 when he handed over the documents, was convicted in July on 20 counts including espionage and theft.
He was found not guilty on the most serious charge, aiding the enemy, which had carried a possible sentence of life in prison without parole.
The classified material that shocked many around the world was a 2007 gunsight video of a US Apache helicopter firing at suspected insurgents in Baghdad. A dozen people were killed, including two Reuters news staff, and WikiLeaks dubbed the footage "Collateral Murder."
The release of the documents catapulted WikiLeaks and its founder, Julian Assange, to the international spotlight and heightened a debate on government secrecy. A US rights group has said Manning should be a candidate for this year's Nobel Peace Prize.
Prosecutors have contended that when Manning turned over the secret documents he had put national security, including overseas intelligence operatives, at risk.
His defense argued that the slightly built soldier had hoped to spark a broader debate on the role of the US military and make Americans aware of the nature of wars in Iraq and Afghanistan.
According to defense testimony, military supervisors ignored erratic behavior by Manning that included trying to grab a gun during a counseling session.
Defense attorneys had argued that such actions showed that Manning, who is gay and was increasingly isolated while deployed to Iraq, was not fit for duty overseas.
During a pretrial hearing, Lind reduced Manning's sentence by 112 days because of harsh treatment after his arrest in 2010. He likely will be imprisoned at the US Disciplinary Barracks at Fort Leavenworth, Kansas.
Earlier this year, Manning pleaded guilty to lesser charges but military prosecutors continued their effort to convict him on more serious counts.
Manning apologized to the court for what he had done, saying, "I understand I must pay a price for my decisions."
The trial is winding down at the same time the United States is seeking the return of Edward Snowden, a former National Security Agency contractor who disclosed details of secret US programs that included monitoring Americans' telephone and Internet traffic. Snowden has been given temporary asylum in Russia.