During the conflict, the Kurdistan region -- home to US troops and numerous foreign oil companies -- was a primary target for drone attacks, carried out mostly by Tehran-backed Iraqi armed groups.

Many oil operations in Iraq were halted, with several fields struck by drones.

Kurdistan regional government spokesperson Peshawa Hawramani said that Gulf Keystone Petroleum, a subsidiary of Britain's Gulf Keystone, "started production today at the Shaikan field", one of the largest in the Kurdistan region.

He said Norway's DNO should resume its activities at the Tawke and Peshkabir oil fields on Friday, while the US firm HKN should restart production at the Atrush field on Sunday.

The US firm Hunt Oil will resume operations on July 8, Hawramani said.

He added that the delay in resuming production was due to the "substantial damage from earlier attacks on oil facilities".

A founding member of the OPEC oil cartel, Iraq is hugely dependent on its oil exports, accounting for some 90 percent of its budget revenues.

Before the start of the Middle East war on February 28, most of its output -- roughly 3.5 million barrels per day in normal times -- had been exported via the Strait of Hormuz.

But the war and Iran's ensuing blockade of Hormuz choked off shipments and prompted significant production cuts.

After a recent deal between Washington and Tehran to end the fighting, Iraq now hopes to return within two months to its previous production levels.

rh/amj