The funeral of Saleh al-Ogaili has taken place in Baghdad
Iraq's prime minister has vowed to track down the perpetrators of a bomb attack that killed an MP from the bloc of Shia cleric Moqtada al-Sadr.
Nouri Maliki said a high-level inquiry into the assassination of Saleh al-Ogaili in Baghdad was under way.
Police said the bomb had been placed on a motorcycle and exploded as a convoy carrying Mr Ogaili drove past.
He suffered severe head wounds and was later pronounced dead. He is the first MP to be killed in Iraq for 18 months.
"We reaffirm our determination to get at the hotbeds of terrorism and crime, and arrest and prosecute the killers and bring them to justice," Mr Maliki said in a statement.
Police said two other people died in the blast, which took place in the Habibiyah district, near the Sadr movement's stronghold of Sadr City.
The last MPs killed in Iraq were among a group of eight people who died after a suicide bomber attacked the cafeteria at the Iraqi parliament on 12 April 2007.
In another roadside bombing north of Baghdad on Thursday, the leader of an armed Sunni group working with US forces against al-Qaeda militants was killed along with two of his children and a nephew, police said.
Abbas Khudair led a Sahwa - or Awakening - group in the Uthaim area of Baquba, in the restive capital Diyala province.