Iraq's prime minister has said he hopes Saddam Hussein gets "what he deserves" for "crimes against the Iraqi people", ahead of Sunday's expected verdict.
Nouri Maliki has called for calm ahead of the verdict
In a TV message urging calm, Nouri Maliki said Iraqis should mark it in a way that "does not risk their lives".
Military leave has been cancelled amid heightened security, as Saddam Hussein supporters threatened more violence if he were sentenced to death.
In fresh unrest, police have killed 53 insurgents near Baghdad, officials say.
The interior ministry said four policemen also died and 16 insurgents were captured in fierce fighting in the southern outskirts of the city.
A spokesman said police had been acting on information that a number of people were being held hostage in the area, but he said officers had found no sign of any captives.
Saddam Hussein is being tried on charges of crimes against humanity
The verdict in the first of Saddam's trials is due to come amid increased violence - 83 bodies, some showing signs of torture, were found in Baghdad alone in the past 36 hours.
The former president and co-defendants are accused of ordering the deaths of 148 Shias in 1982 in the village of Dujail, following an assassination attempt on Saddam Hussein.
The verdict is also expected two days before mid-term elections in the US, where Iraq has been a hot topic.
Leading conservatives have been challenging President George W Bush's conduct of the war.
Former Pentagon adviser Richard Perle, who was originally in favour of the invasion, has said US policy in Iraq has turned into a disaster.
On Sunday Baghdad's civilian airport will be closed and a 12-hour-long curfew imposed in the capital and three provinces - among them Salahuddin, which includes Saddam Hussein's hometown Tikrit.
The curfews are to be enforced from 0600 (0300 GMT), with vehicles and pedestrians banned from the streets.
Correspondents say a violent reaction would not be surprising in Salahuddin, north of Baghdad, nor in Anbar to the west of the capital - where no curfew has been announced.
The BBC's Hugh Sykes in Baghdad says it will be hard to enforce a curfew in Anbar as many of Saddam's former police, senior army officers and Baath Party officials lived in the two main towns there - Falluja and the provincial capital Ramadi.
But elsewhere, there may be celebrations as when Saddam Hussein's sons, Uday and Husay were killed, our correspondent says.
A member of Saddam Hussein's defence team said the overall atmosphere and military measures being taken suggested a death sentence was about to be passed.
Najeen al-Nuaimi told al-Jazeera television they would appeal against the verdict, but "to a committee that is unfortunately composed of members of the same committee that is currently trying the president".