Two security officials have been killed and eight injured after a convoy carrying an Arab League delegation was attacked by gunmen in Baghdad.
The Arab League is in Iraq for a conference on reconciliation
They were reported to be on their way to a meeting with leaders of the Sunni Arab community when they came under fire from unknown gunmen.
No members of the delegation were hurt in the attack.
The Arab League diplomats are in Baghdad to prepare for a conference on Iraqi reconciliation.
They are also preparing for a visit to the country by Arab League secretary general, Amr Moussa.
It would be the first visit by Mr Moussa since the US-led invasion of Iraq in March 2003.
The violence comes as Iraqis prepare to vote on a new constitution on Saturday.
Shia and Kurdish officials continue to negotiate with Sunni Arab leaders over last-minute additions to the document in an attempt to win over Sunni support for Saturday's referendum.
US officials are acting as mediators between the groups during the talks.
Sunni leaders say many Sunnis plan to vote against the constitution over fears the document will allow two oil-rich and nearly autonomous regions to emerge - benefiting Kurds in the north and Shias in the south.
More than 300 people have died in violence over the last two weeks
Sunni insurgent groups have called for a boycott of the vote.
"They [the US] should not think they will change the attitude of the Sunnis," said Saleh al-Mutlak of the Sunni National Dialogue after a meeting with the US Ambassador, Zalmay Khalilzad.
The charter can be defeated if two-thirds of voters reject it in any three of Iraq's 18 provinces. Sunnis constitute a majority in four provinces.
At least 15 Iraqis and a US soldier have been killed in a string of attacks across Iraq, reports say.
These include a suicide car bomb that killed a US soldier at a checkpoint outside Baghdad's highly fortified Green Zone.
Five mortar shells were fired at a hotel in Hilla, south of Baghdad, which houses the US consulate in the city. No casualties were reported.
And at least one Iraqi policemen was killed in a series of shootings across the Iraqi capital.
More than 300 Iraqis have been killed in insurgent attacks over the last two weeks, according to the Associated Press news agency.