Ten Iraqi bodyguards and drivers were killed and two foreign telephone engineers were missing, feared kidnapped, after gunmen ambushed a convoy in a Baghdad tunnel.
Eight more Iraqis were killed in attacks nationwide, while the 11 bodies of policemen and soldiers were discovered in a makeshift grave.
Two foreign engineers were kidnapped in the ambush on the three-car convoy of the Iraqna mobile phone company, an interior ministry official said, adding that three drivers and seven bodyguards were killed.
Shamel Hanafi, chief commercial officer for Iraqna, told AFP the engineers were from Malawi and Madagascar. "We don't know whether they were kidnapped, or whether they ran away or are hiding after the attack," he said.
The government in Malawi, which has no diplomatic relations with Iraq, said it was investigating the report.
The convoy had been on its way to the western suburb of Abu Ghraib to repair a transmitter station when the attack occurred, officials at the hospital were told.
In other violence Wednesday, Sunni tribal leader Mohammed Sadek al-Batah from Al-Anbar province was shot dead in a flat in western Baghdad along with a nephew and an associate.
In Saadiya, northeast of Baghdad near the Iranian border, a roadside bombing targeting a police patrol killed one policeman and wounded five.
The US army reported finding the bodies of 11 men in police army uniforms, in a makeshift grave near Attarmiyah, some 50 kilometers north of Baghdad.
All the victims were found bound and blindfolded, but there was no immediate word on when they were killed.
The US military also reported the death of a US soldier of non-combat injuries.
Further light was shed on the downing of a US Apache helicopter with the US-based ABC television reporting it was shot down by a Russian SA-7, a surface-to-air missile that was common in the arsenals of the Iraqi army under Saddam.
Two crew members were killed in the incident, the third involving a US helicopter in Iraq in 10 days.
There are hundreds, possibly thousands of the Russian SA-7 missiles unaccounted for in Iraq.
Meanwhile, officials in Iraqi Kurdistan said they had sent samples to Jordan for checks after a girl died showing symptoms of avian flu, even though initial tests proved negative.
And Foreign Minister Hoshyar Zebari has called on Iran to release nine border guards seized during an incident on the Shatt Al-Arab waterway, near the Gulf, his ministry said.
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