The US Army published dozens of documents online Wednesday in the case of WikiLeaks suspect Bradley Manning, after media outlets and other groups had criticized a lack of transparency.

The move came in response to multiple Freedom of Information Act (FOIA) requests related to the case against Manning, who stands accused of passing a trove of secret files to Julian Assange's anti-secrecy WikiLeaks website.

Among the organizations that demanded access to the pre-trial documents were The Washington Post, CNN and the Center for Constitutional Rights, which all said they had been prevented from informing the public about the case.

Such documents have been sealed based on requests either by the prosecution or defense lawyers in the case against Manning, which is being heard in a military court at Fort Meade, Maryland, north of the US capital Washington.

In federal civilian court, similar types of documents are nearly always made public.

Even in the military commissions at the Guantanamo detention facility, where pre-trial hearings in the case against the 9/11 plotters are being heard, military lawyers have made such documents available.

On Wednesday, 84 court orders and rulings were released in the Manning case, including a partial transcription of a deposition made by Manning.

The 25-year-old Army private faces a slew of charges, including "aiding the enemy," for allegedly leaking hundreds of thousands of sensitive US military and diplomatic documents to WikiLeaks.

He was arrested in May 2010 while serving as an intelligence analyst near Baghdad and subsequently charged over the largest leak of restricted documents in American history. The trial is expected to begin in June.

"Due to the voluminous nature of these documents, it will take additional time to review, redact, and release all of the responsive documents," the Army said in a statement, adding that 500 documents have been released thus far.

During Wednesday's hearing at Fort Meade, Judge Denise Lind dealt the defense a blow when she rejected their claim that the documents allegedly leaked by Manning were incorrectly marked top secret.

"Evidence of overclassification is not relevant," she said.

The proceedings at Fort Meade are shown to reporters via closed circuit television with a slight delay, so the transmission can be cut if sensitive matters are discussed.

Prosecutors had asked that hearings be closed when classified information is to be discussed.

Prosecutor Ashden Fein said that of 141 possible witnesses, "some form of classification" should be used for testimony from 73 of them, though "not necessarily all their testimony."

Manning is expected to offer a revised plea proposal Thursday.

The most serious of the 22 charges against him, "aiding the enemy," carries a maximum sentence of life imprisonment, but Manning's team is trying to have that charge dropped.