"The president ordered deployment of the armed forces to protect life and property of the people, keep alive economic activities, seize illegal weapons and control terrorists."
The statement said the armed forces were asked to carry out the order to help the law enforcement agencies. It did not state exactly when the army would be deployed.
It also said the civil administration had been asked to prepare for the deployment and keep magistrates ready to help troops on duty.
The president heads an interim government in charge of holding the election due on January 23 in a free, fair and peaceful manner.
At least 44 people have been killed and hundreds injured in clashes between rival political activists since late October. A 15-party alliance, led by Sheikh Hasina of the Awami League, has threatened bigger protests including a siege of the presidential palace if the president failed to remove election officials it accuses of a bias towards its rivals.
The armed forces were deployed a couple of weeks before the last election in 2001 to recover arms across the country. But this time the armed forces have been called in much earlier.
The decision followed Bangladesh opposition parties' latest threat of non-stop protests to force the country's interim government to keep its promises on electoral reform.
But late on Saturday, an opposition spokesman, Abdul Jalil, told reporters that they had extended the deadline until Sunday evening after the interim cabinet held meetings throughout the day to prevent a new series of protests.
Jalil was not available to comment on the military's deployment.
CM Shafi Sami, a member of the interim cabinet, told reporters on Saturday that they expected to fulfil the opposition's demands by Sunday.