"At approximately 18:45 (1545 GMT), a drone struck the site, according to preliminary information," said Ramak Ramadan, district chief of Chamchamal where the Khor Mor complex is located.

The attack "targeted a fuel storage tank", he added.

Four workers were wounded, said another local official who requested anonymity because he is not allowed to speak to the media.

A security source confirmed the attack against the site which is owned by the United Arab Emirates firm Dana Gas.

There was no immediate claim of responsibility.

The gas field lies between the cities of Kirkuk and Sulaimaniyah, in a region administered by Kurdish authorities.

Unclaimed Katyusha rocket attacks targeted the same complex several times in recent years without causing significant damage.

In January, two Katyusha rockets targeted the gas field, causing a blaze, but no casualties were reported.