Preliminary hearings in the first criminal cases against prisoners held at the US naval base at Guantanamo Bay in Cuba are expected to begin in August month, a senior defense official has said. The hearings would be the initial legal step in the first US military tribunal - formally called a military commission - since World War Two and would set the parameters for trial before a panel of five officers. "We are making plans for the first preliminary hearings as early as late next month," said a senior defense official said on Thursday. The Australian government said it expects US military court proceedings against Australian Guantanamo inmate David Hicks to start the week of August 23, according to Australian news reports. Hicks, 28, was charged in June with three counts: conspiracy to commit war crimes, attempted murder and aiding the enemy. Three others prisoners also are facing criminal charges brought by the United States. **Charges faced*** Salim Ahmed Hamdan of Yemen is charged with one count of conspiracy to commit murder, attacks on civilians and terrorism. The Pentagon said Hamdan provided security for al Qaeda leader Osama bin Laden and other top members of the network that carried out the 11 September 2001 attacks on the United States. Ali Hamza Ahmed Sulayman al Bahlul of Yemen and Ibrahim Ahmed Mahmoud al Qosi of Sudan were charged in February with a single count each of conspiracy to commit war crimes. The United States holds at Guantanamo 594 foreign nationals detained in what US President George W. Bush calls the global war on terrorism. Most were captured in the US-led war in Afghanistan. Their imprisonment at the base began in January 2002. Nearly all have been held without charges or access to lawyers. Human rights groups have charged that the rules for the tribunals are rigged to hamstring defense lawyers and produce convictions. The Pentagon has pledged "full and fair" trials. Separate military panels were expected to begin as early as Friday reviewing, on an annual basis, whether or not to release each of the Guantanamo prisoners or continue holding them. **PHOTO CAPTION*** A guard enters the main gate of Camp 5, a maximum security facility at Camp Delta at the U.S. Naval Base Guantanamo Bay, Cuba July 28, 2004. (REUTERS)