Updated

Gunmen in Iraq killed 15 Iranian pipeline workers and two Iraqi guards northeast of Baghdad on Friday, officials said. Separate attacks across the country killed 23 other people.

A senior security official said the nighttime attack on the pipeline workers took place in the al-Nida area, where gunmen opened fire on the men working on the gas pipeline planned to connect Iraq's gas network to supplies from neighboring Iran.

Al-Nida is about 145 kilometers (90 miles) northeast of Baghdad. Four people, including two Iranians were wounded also in the attack.

Earlier Friday, twenty-two Iraqi suspects facing terrorism charges escaped from a prison in northern Baghdad after killing a security guard, but most were rearrested later in the day, officials said.

The stunning jailbreak from al-Adela prison triggered a police manhunt backed by helicopters that ended with one of the escaped prisoners dead and 13 rearrested. Eight remain at large.

The prisoners had lured a guard into their cell while his comrades were sleeping, claiming an inmate there was critically ill. They then stabbed him to death, two senior security officials said.

Jailbreaks are frequent in Iraq and, as with other security breaches, they have cast doubts on the ability of the authorities to secure the country, mired in sectarian tensions.

Also Friday, a car bomb went off near a security checkpoint in the western city of Ramadi, killing five policemen and wounding seven others, said police officials.

In a drive-by shooting in western Baghdad, gunmen shot and killed two government employees in their car. And police said a bomb exploded near an out-door market in Madain area, just south of Baghdad, killing one person and wounding four.

A car bomb exploded inside a fish market in Baghdad's southeastern Shiite-majority suburb of Nahrwan, killing four and wounding 14, police said.

In the western city if Ramadi, a car bomb went off near a security checkpoint, killing five policemen and wounding seven others, said police officials

At night, six people were killed and 18 others were wounded in a car bomb explosion in a commercial street in a town, just south of Baghdad.

Medics in nearby hospitals confirmed the casualty figures for all the attacks. All officials spoke on condition of anonymity because they were not authorized to talk to media.

Deadly insurgent attacks have been on the rise since a security crackdown on a Sunni protest camp in a northern town last April.