Iraqi authorities say the leader of the main Sunni bloc in parliament has been shot and killed outside a mosque in Baghdad, along with four bystanders and the gunman.
An official with the lawmaker's party says Harith al-Obeidi was killed after leading Friday prayers at the al-Shawaf mosque in the Yarmouk area of the Iraqi capital.
Police and party officials from his National Accordance Front said the gunman, who appeared to be a teenager, opened fire on Obeidi as he left the mosque. They say mosque guards chased the assailant, who detonated a grenade and was killed as he fled.
Obeidi was the head of the main Sunni Muslim bloc in Iraq's parliament. He also was a member of parliament's human rights committee.
Prime Minister Nouri al-Mailiki ordered an investigation into the attack, which he called "a futile attempt to incite sectarian strife."
The attack came a day after the prime minister warned that violence could increase in the coming weeks as U.S. troops prepare to withdraw from urban areas.
Mr. Maliki told a meeting of Iraqi commanders in Baghdad Thursday that attacks likely will intensify as insurgents try to give the impression that Iraqi forces are a failure.
U.S. forces are planning to pull out of Iraqi cities by the end of June, in line with an agreement reached with Iraq's government.
U.S. President Barack Obama has pledged to withdraw all American combat troops from Iraq by the end of August 2010.
Some information for this report was provided by AP and Reuters.