Ali Musa Salman, director general of the ministry, was killed after leaving his home in central Baghdad on Sunday. His driver was also killed while three others were wounded.
Elsewhere in Iraq, violence continued as four police officers were killed by a roadside bomb in the predominantly Sunni city of Samarra, about 100km north of Baghdad, police Lieutenant Qasim Muhammad said.
A roadside bomb blast on Sunday killed one Iraqi civilian and wounded another near Aiyun, a village 55km west of the northern oil-rich city of Kirkuk, said army Major-General Anwar Muhammad Amin.
Amin said he also escaped an assassination attempt late on Saturday when two roadside bombs exploded near his military convoy between Kirkuk and Hawija to the southeast.
Five mortars, apparently aimed at a police special forces base, missed their target and struck southwestern Baghdad's al-Alam residential area late on Saturday, wounding five civilians, police Captain Talib Thamir said.
The violence also has taken its toll on reconstruction efforts, and fighters targeting oil lines, electricity plants and other infrastructure projects have delayed US plans to invest $21 billion in resources for the country's reconstruction, a US official said.
Bill Taylor, director of the US-led Iraq Reconstruction Management Office, said on Saturday that ceaseless attacks - the military has said they average 70 a day - have led to skyrocketing security demands, with up to 16% of all project costs expected to be spent on protection.
The Sun newspaper published
more photos of Saddam Hussein
So far, $7.5 billion of that has been paid to contractors to perform works. Rebuilding, training and equipping Iraq's own security forces will eat up $5 billion, he added.
"We are paying more for security than we should," Taylor
said. "The fact is that the security is not good."
Saddam Hussein pictures
There were fears the publication on Friday and Saturday of
pictures showing the imprisoned Saddam Hussein, including one where he is clad only in his underwear, could further fuel
The new pictures in Britain's The Sun included one of Saddam Hussein seen through barbed wire, wearing a white Arab robe, and another of Ali Hassan al-Majid, better known as "Chemical Ali" for his alleged role in gassing Kurds, in a bathrobe and holding a towel.
The newspaper also ran pictures of Huda Salih Mahdi Ammash, a biotech researcher, who was allegedly involved in trying to develop biological weapons for Saddam Hussein.
The Sun said the photos were provided by "US military sources" it did not identify, who hoped their release would deal a body blow to the fighters.
The US military condemned publication of the photos and ordered an investigation into the leak.