Gunmen attacked headquarters of a contracting company in Akkas gas field in Iraq's western province of Anbar, killing two engineers and kidnapping another, a provincial police source told Xinhua on Tuesday.

The attack occurred late on Monday when gunmen in two vehicles carrying assault rifles attacked the headquarters of a local company hired by the South Korean firm of KOGAS to work at the desert area near the Syrian border, the source said on condition of anonymity.

The attackers shot dead two engineers and kidnapped a third before they set fire to the vehicles and offices of their headquarters, the source said.

No group has so far claimed responsibility for the attack. However, Sunni insurgent groups including al-Qaida are partially taking control of the vast desert area in western Iraq.

In October 2011, the Iraqi Oil Ministry singed a 20-year deal with the South Korean Gas Corp (KOGAS) to develop Akkaz natural gas field in Anbar province.

The Akkas gas field has 5.6 trillion cubic feet (156 million cubic metres) of natural gas.

The attack in Akkas was the second major attack that took place on Monday, as a suicide bomber rammed his explosive-laden tanker truck near the police headquarters in Salahudin's provincial capital city of Tikrit, some 170 km north of Baghdad, killing up to 11 people and wounded some 70 others. Endi