On May 28, talks between US and Iranian officials are to begin in Baghdad to discuss the security situation in Iraq. Washington has often accused Iran of arming groups and militias.
In Iraq's capital, two Iraqi journalists working for ABC News were ambushed as they drove home from work, the American television network announced on Friday.
Unidentified assailants waylaid the car carrying Alaa Uldeen Aziz, 33, cameraman, and Saif Laith Yousuf, 26, soundman, and shot them dead, the network said.
The fighting in Baquba began about 7am local time, when fighters opened fire on a US-Iraqi base in the centre of the city, about 60km northeast of Baghdad.
|Yousuf, left, and Aziz were ambushed as|
they returned home from work [AFP]
About a half hour later, US reinforcements arrived, killing at least six fighters, the Iraqi army officer said. He spoke on condition of anonymity because he is not authorised to speak to the media.
Residents said the fighting sent smoke billowing up from neighbourhoods in the area.
One resident, who spoke on condition of anonymity for fear of reprisals from fighters, said he heard heavy machinegun fire and then men shouting "Allahu Akbar".
Others said they saw US armoured vehicles driving through the street, while aircraft flew overhead.
The fighting ended about noon, but several hours later suspected insurgents fired a mortar round at a nearby police headquarters, the army officer said. No casualties were reported.
Hunt for soldiers
Meanwhile, the massive search for three missing US soldiers believed to have been kidnapped by al-Qaida-linked fighters entered its seventh day.
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Colonel Michael Kershaw, the commander of the 2nd Brigade Combat Team, 10th Mountain Division who was overseeing the mission, said the teams were talking to local Iraqis, hoping to find information that would lead them to the soldiers.
While the search was under way on Thursday, three American soldiers were killed and another was wounded in a roadside bombing south of Baghdad, the US military reported.
The statement provided no more details, and it was unclear if the victims were part of the search.
In other news, a 24-hour curfew remained in place in Mosul, 360km northwest of Baghdad, for a third day on Friday.
|Baquba has been one of the hotbeds of Sunni|
resistance to US military presence [AP]
It was imposed after fighters used five suicide vehicle bombs, mortars and small arms fire to destroy two bridges and attack a police station and a jail where suspected fighters were being held.
The attacks killed 15 fighters, 10 Iraqi policemen, one Iraqi soldier and one civilian.
About 47 people were wounded, the US military said.
A suicide car bomber hit a police patrol in the Sunni-dominated town of Jurf al-Sakhar, 65km south of Baghdad, killing three officers and wounding two, police said.
In the oil-rich city of Kirkuk, 290km north of the Iraqi capital, drive-by shooters killed an Iraqi army officer as he was heading to work, police said.