A Qatar-based drilling company says a fire has broken out on an offshore rig run by its subsidiary, injuring six workers.

Gulf International Services announced the fire in a statement Monday published on the Qatar Stock Exchange. It says workers put out the fire at the GDI-3 rig, which was being prepared for movement.

The statement did not say when the fire started or where the rig was. Phone numbers listed for the company and its affiliate rang unanswered Monday afternoon and officials did not immediately respond to email queries about the fire.

GIS is partly owned by state-run Qatar Petroleum, which oversees oil and gas exploration in the small OPEC nation. A July 2015 accident saw another GIS rig suffer a "punch-through incident" and partly collapse.