International oil companies based in Iraq, Opec's second-largest producer are pulling out US staff following the assassination of Iran's top military commander in Baghdad on Friday.
Washington, which engineered the drone strikes that killed Qassem Suleimani, the head of the elite Quds Force - part of the Islamic Revolutionary Guard Corps - urged its citizens to depart Iraq "immediately".
A number of American workers are deployed across oil sites in Iraq, which has US majors Exxon Mobil and Chevron operating large fields in the country.
A spokeswoman for Exxon Mobil, the lead contractor in West Qurna 1, one of Iraq's largest oil fields, west of the southern province of Basra told The National in a statement that production continued "normally".
"We are closely monitoring the situation. ExxonMobil has programmes and measures in place to provide security to protect its people, operations and facilities," she said.
The company declined to specify whether its American staff had been evacuated.
In May, Exxon withdrew around 60 workers, mostly US nationals, after Washington order non-emergency personnel to leave Iraq citing unspecified threats.
Iraq's oil ministry said that some US personnel had left Iraq following the death of Suleimani, but production remained unaffected.
A spokesman for German firm Siemens, which operates in Iraq, said that its operations "haven't been disrupted and no staff have been evacuated".
"We are monitoring the situation and will always take appropriate measures to ensure our workers and facilities are safe and secure," he added.
Shell, which is a joint operator of the Basrah Gas Company and BP declined to comment.
Iran and Iraq produced 2.13 million barrels per day and 4.65 million pbd of crude in November 2019, respectively, and combined accounted for nearly 8 per cent of global oil liquids supply in November 2019, according to a research note by UBS.
"Market participants are concerned that the tensions between Iran and the US could impact the political stability of Iraq and oil production in the second-largest OPEC producer after Saudi Arabia," said Giovanni Staunovo, a commodity analyst at the Zurich-based lender.