Five planes carrying around 40 foreign nationals working alongside the Basra Gas Company were flown out of the country on Wednesday, an industry source and an airport source said.

The industry source said it was due to days of protests over late salary payments at one of the fields where BGC, a joint operation between Shell, Mitsubishi and Iraq's state-owned South Gas Company, is extracting gas.

"As a result of a security breach at the accommodation camp of Basra Gas Company, we have temporarily relocated Shell secondees," a spokesman for Shell said.

"All staff and contractors are safe and BGC production is not impacted," the spokesman added, declining to specify how many employees were evacuated and where they were flown to.

Commercial flights in Iraq have been halted since late March as part of a nationwide lockdown to stop the spread of the novel coronavirus, which has killed more than 130 people and infected more than 3,000 across the country.

Iraq has been hit hard by the collapse of world crude prices in the wake of the coronavirus crisis as as it relies on its oil revenues to fund more than 90 percent of government expenses.

Prime Minister Mustafa Kadhemi said this week that public salaries for the month of May would be paid as usual after fears that last month's record-low oil revenues would force the government to halt public sector wages.

In late March, authorities asked international companies extracting oil and gas in Basra to accept a delay in payments for the first two quarters of this year.

They also requested companies cut their work budgets by 30 percent, prompting fears of lay-offs.

In Basra, Iraqi gas workers have been protesting for several days as a dispute over payments has delayed their salaries.