Some 40,000 security forces, both Iraqi and coalition, are being deployed in Baghdad as part of the measures, known as "Operation Forward Together."
The operation -- part of Prime Minister Nuri al-Maliki's plan to curb insurgent attacks -- comes after Al-Qaeda warned of massive attacks to avenge the killing last week of its leader in Iraq, Abu Mus'ab al-Zarqawi.
In spite of the security operations, a car bomb killed two people in northern Baghdad.
Outside the capital, a journalist was killed on June 13 in drive-by shooting in Al-Fallujah. Ibrahim Seneid, an editor for the "Al-Bashara" newspaper, is the latest victim in a long series of attacks on the media.