"We are about to make changes in the high and middle positions of those responsible for security, and the security strategy," Maliki said on Monday at a news conference in Baghdad.
"We will discuss this matter in the cabinet session tomorrow (Tuesday) to take decisions," Maliki said, without providing further details.
"I assure the Iraqi people that they (militants) will not be able to return us to the sectarian conflict" that killed tens of thousands of people in Iraq in past years, he added.
A car bomb exploded in Shaab, a Shiite area in north Baghdad, at around the time Maliki spoke, killing 12 people and wounding at least 20, officials said -- just the latest in a wave of bombings on Monday.
Two car bombs went off in the main southern port city of Basra, killing 13 people and wounding 48, while a wave of other bombings hit Baghdad, killing at least 11 people and wounding 102.
In Balad, north of the capital, a car bomb exploded near a bus carrying Iranian pilgrims, killing four people and wounding at least 17.
Iraq is home to some of the holiest sites in Shiite Islam and is visited by hundreds of thousands of foreign pilgrims every year, most of them from neighboring Iran.
Three Sahwa anti-Al-Qaeda fighters were killed and 14 wounded in two separate attacks north of Baghdad, and a roadside bomb in the northern city of Mosul wounded three people.
Monday's violence comes after 24 police were killed overnight.
Police Lieutenant Colonel Majid al-Jlaybawi said police and soldiers carried out a joint raid to free kidnapped police officers in Anbar province, west of Baghdad, but clashes ensued.
Twelve kidnapped policemen were killed and four wounded, although it was not immediately clear if they were caught in crossfire, killed by their abductors, or a combination of the two.
In Haditha, a town in Anbar province, gunmen attacked a police station, killing eight police,