Iraq's prime minister has warned that a plague of sectarianism is threatening Arab nations, after the most widespread violence there since US troops left.
Nouri Maliki said sectarian conflict had returned to Iraq "because it began in another place in this region" - an apparent reference to Syria.
The violence has left some 170 people dead across the country since Tuesday.
On Saturday, at least five anti-al-Qaeda Sunni militiamen and three security forces personnel were killed.
Police said the first attack saw gunmen open fire on a checkpoint near the city of Tikrit manned by members of the local Awakening Council.
Awakening Councils, which were set up by Iraq's Sunnis to combat insurgents linked to al-Qaeda, have been seen as a key factor in reducing violence across the country since 2006.
In Saturday's second attack, three army intelligence personnel were stopped by gunmen while travelling in a civilian vehicle near an anti-government protest camp in the city of Ramadi, police said.
A gunfight soon erupted, in which the soldiers were killed.
'Wind of sectarianism'
In a televised speech following the latest violence, Prime Minister Maliki condemned sectarianism as an evil that was being brought back to Iraq.
"Sectarianism is evil, and the wind of sectarianism does not need a licence to cross from a country to another, because if it begins in a place it will move to another place," he said.
"Strife is knocking on the doors of everyone, and no-one will survive if it enters, because there is a wind behind it, and money, and plans," he added, without giving details.
Awakening Council chief Sheikh Wissam al-Hardan was meanwhile quoted by state television as saying that if those responsible for killing soldiers in the past week were not handed over, it would "take the requested procedures and do what it did in 2006".
On Friday, the UN envoy to Iraq, Martin Kobler, urged political and religious leaders "not to let anger win over peace" and exercise restraint, warning that the country was "at a crossroads".
The clashes in several towns and cities were sparked by an army raid on an anti-government protest camp near the northern town of Hawija on Tuesday that left 50 people dead.
The protesters were calling for the resignation of Mr Maliki, a Shia, and denouncing the authorities for allegedly targeting the Sunni community.
Although the violence is less deadly than that seen during the heights of the insurgency in 2006 and 2007, it is the most widespread since the US military withdrawal in 2011.