Unrest has reached a level this year not seen since 2008, when Iraq was just emerging from a period of brutal sectarian killings, and the surge has raised fears the country is falling back into all-out conflict.
Gunmen in three vehicles attacked the gas pipeline workers near Baladruz, northeast of Baghdad, killing 15 Iranians and three Iraqis, police officers said.
The attack also wounded five Iranians and three Iraqis, the added.
South of Baghdad, a car bomb exploded in Madain, killing at least six people and wounding at least 13, while another car bomb near a fish market in Nahrawan killed four people and wounded at least 12.
A police colonel said detainees had seized weapons from guards early today, killing two, after which 26 people arrested for "issues related to terrorism" escaped.
Security forces killed one escaped detainee and captured 14, the colonel said, and a medical official confirmed two guards and a detainee had been killed.
The interior ministry said 22 suspects had escaped, but one was killed and all but three others captured.
In July, militants launched coordinated assaults on two prisons near Baghdad, sparking clashes with security forces that lasted for hours.
In the Ghazaliyah area of west Baghdad, gunmen shot dead two people today, one of them a trade ministry employee, while gunmen killed a woman in her home near the capital.
And a suicide bomber detonated an explosives-rigged vehicle near a group of security forces members in Ramadi, west of Baghdad, killing a civilian and two soldiers and wounding four policemen and three soldiers.
More people died in the first eight days of this month than in the whole of last December, according to AFP figures based on security and medical sources.
