Authorities in Iraq say masked gunmen have shot dead at least 17 oil and gas workers -- most of them Iranian -- about 150 kilometers northeast of Baghdad.
The Reuters news agency quotes a surviving worker as saying the attackers arrived Friday night outside of Muqdadiya in three cars and started shooting at workers digging a trench to extend a pipeline between Iraq and Iran.
Eight other workers survived the attack and are hospitalized.
There was no immediate claim of responsibility. But officials are quoted as saying the attack bears the hallmarks of the al-Qaida affiliate that has mounted numerous attacks on Iraqi towns and cities since April.