Iraq's state minister for provincial affairs, Saad al-Hardan, escaped an attempt on his life in southern Baghdad on Wednesday.
His convoy came under attack in al-Qadissiya district, south of Baghdad, Iraqi security sources told Aljzeera.
The Sunni Muslim minister was not in the convoy at the time of the attack near the highly fortified Green Zone, which houses Iraqi government offices and the US and British embassies.
Medical sources at al-Yarmuk Hospital in Baghdad said seven people, including four of al-Hardan's bodyguards, were seriously wounded.
In a last-minute deal was clinched on Tuesday after days of intense negotiations, Shia Muslim and Kurdish leaders agreed to concessions that would see parliament consider amendments to the charter after fresh legislative elections are held in December.
In a separate incident, head of the Samarra tribal council, Hikmat Mumtaz, was killed by armed men in al-Muatasim neighbourhood of the Iraqi city of Samarra, a police source said.
The armed men opened fire at his car while he was on his way home, the source added.
The main Sunni Muslim Arab party said it would now be calling for a "yes" vote on Saturday, when 15.5 million registered voters are to cast their ballots on the document that lays out the legal framework for the new Iraq.
"There was an agreement and we are calling for a 'yes' vote," Ayad al-Sammarai, spokesman for the Iraqi Islamic Party, told AFP. "It will give us the opportunity to review the constitution."
Source: Aljazeera + Agencies