Baghdad (CNN) -- Five Iraqis, including three police officers, were killed Tuesday, according to officials with the Iraqi Interior Ministry.
In Baghdad, Col. Mustafa Saeid, an Interior Ministry official and police officer, was shot to death by gunmen while driving on a highway in the eastern portion of the city, officials said. Roadside bombs attached to civilian cars also killed drivers in southern and western Baghdad. Two bystanders were injured in the western Baghdad bombing, officials said.
In addition, a roadside bomb attached to a car in southeastern Baghdad wounded four people, including two police officers.
In Falluja, a sticky bomb attached to a police officer's car in the central city exploded, killing the officer instantly and wounding two bystanders. In addition, a sticky bomb attached to a car killed another police officer in eastern Falluja, officials said. Falluja is located in Anbar province, about 60 kilometers (37 miles) west of Baghdad.
On Monday, violence across Iraq left 20 people dead and wounded 37, authorities said.
The latest wave of violence, especially in the past two weeks, has raised questions over the ability of Iraqi security forces to protect the country as U.S. troops prepare to leave Iraq. Under a bilateral agreement between the Iraqi government and the United States, American troops are scheduled to depart Iraq by year's end. But if violence increases and instability persists, it is possible both countries could agree to keep some U.S. troops there. About 47,000 U.S. soldiers are currently in Iraq, down from a high of 171,000 in 2003.