Hundreds of protesters broke into Iraq's giant southern West Qurna-2 oilfield , developed by Russia's LUKOIL, early on Monday, sources from the field, police and the state-run Southern Oil Co. said.
Iraqi oil police called in the army to help restore order after the protesters stormed offices and smashed up surveillance cameras, demanding jobs. Construction work at the site was affected.
"At least 400 angry protesters breached the main gate and broke into West Qurna oilfield," an official at West Qurna Phase 2 told Reuters. "Most of the foreign and local staff left the field as a safety measure and work was significantly affected."
Police sources said the protesters trashed the offices of an Iraqi company hired by Samsung Engineering before trying to break into the South Korean builder's headquarters, throwing stones at the main gate.
Police and security guards held them back.
"Protesters were on a rampage. They were asking for jobs. We got scared and left and escaped to other headquarters in Basra," a West Qurna worker told Reuters.
Samsung has a major contract with Russia's Lukoil to build crude facilities at West Qurna-2, which is the world's second-largest undeveloped field with recoverable oil reserves of around 14 billion barrels, according to LUKOIL.
The Samsung contract, worth $998 million, involves construction of an oil export pipeline, a tank farm, a power station and a gas processing plant, and also an oil gathering system, central processing facilities and a water supply system.
Iraq has an estimated unemployment rate of 16 percent,  with 11 percent of its population under the poverty threshold.