The trial of former Iraqi leader Saddam Hussein, which had been due to resume on Tuesday, has been postponed until Sunday, court officials have said.
Saddam Hussein has been on trial since last October
Hearings had been due to resume under a new presiding judge, but the court failed to convene.
A court official said witnesses were still out of the country after the Hajj pilgrimage, which ended 11 days ago.
A BBC correspondent says there are suggestions of a row among the tribunal panel over the replacement chief judge.
Judge Raouf Abdul Rahman, 64, was appointed on Monday to take over from Judge Rizgar Amin, who resigned amid accusations from government officials that he was too lenient towards the defendants.
But some judges on the five-man panel are unhappy with the decision, the Associated Press news agency reports.
It quotes two unnamed judges as saying some members of the panel hope to bring back Judge Rizgar, while others want another judge, Said Hameesh, to step in.
Hours after the court session was expected to begin, court official Raid Juhi told journalists it has been postponed.
He said the delay was because "some of the witnesses who were due to appear today have been unable to attend because some of them were performing the [Hajj] pilgrimage" to Saudi Arabia.
Judge Rizgar's resignation plunged the tribunal into disarray
The BBC's Nicholas Witchell in Baghdad says defence lawyers for Saddam Hussein have made public their concern about the neutrality and independence of the tribunal and they are likely to attempt to press those arguments further when the tribunal sits on Sunday.
Judge Raouf, a Kurd, has not been present at previous hearings but served on a back-up panel and has been following the trial, officials said.
He was born in the town of Halabja, where members of his family were among 5,000 people killed when Saddam Hussein's forces used chemical weapons to crush an uprising in 1988.
Said Hameesh had been expected to take over from Judge Rizgar, but he was sidestepped amid accusations that he belonged to Saddam Hussein's outlawed Baath party, a claim he denied.
Saddam Hussein last appeared in court on 22 December 2005.
The trial has so far heard harrowing accounts of torture and beatings inflicted on villagers following an assassination attempt on the former leader.
Saddam Hussein and seven co-defendants face charges over the 1982 killing of 148 people in the village of Dujail.
If found guilty, the deposed president could face the death penalty.