Twin bombings west of Baghdad killed nine people Friday, most of them anti-Al-Qaeda militiamen, pushing Iraq's nationwide death toll above 400 for a third month, sparking fears of a revival of sectarian war.
The surge in violence has coincided with months of protests by the Sunni Arab minority and a protracted political deadlock which analysts warn could persist until general elections due next year.
The bombings on the outskirts of Ramadi, capital of western Anbar province, are the latest in a spate of attacks which have killed more than 140 people in the past week, including 27 killed on Thursday, mostly in bombings targeting cafes.
The two explosions went off at around mid-day, the first being a magnetic "sticky bomb" attached to the car of a member of the Sahwa.
As onlookers gathered at the scene another device detonated, a common tactic used by militants in Iraq to maximise the number of casualties.
Overall, nine people were killed and 21 wounded, according to militia Colonel Jubeir Nayef and Dr Ahmad al-Aani of Ramadi hospital. Most of the victims were Sahwa fighters, they said.
The Sahwa are a collection of Sunni tribal militias who turned against Al-Qaeda and joined forces with the US military from late-2006 onwards, helping to turn the tide of Iraq's bloody insurgency.
They are paid by the government, and officials have pledged to integrate them into the civil service or security forces. But they are often targeted by Al-Qaeda-linked militants who regard them as traitors.
Also on Friday, a Sahwa officer was found dead south of Baghdad after being kidnapped a day earlier.
The latest attacks pushed the overall nationwide death toll for June to above 400, the third successive month the figure has reached that level, according to an AFP tally based on reports from officials.
Iraq has seen a rise in violence since the beginning of the year, coinciding with rallies among the Sunni Arab minority against what demonstrators see as discrimination by the Shiite-led authorities.
Analysts say a government failure to address protesters' grievances has given militant groups recruitment fodder and room to manoeuvre.