A Katyusha rocket landed inside the Khor Mor gas field in Sulaymaniyah in northern Iraq on June 22 but caused no damage, the city's counter-terrorism service said.

The Pearl Consortium, United Arab Emirates energy firm Dana Gas and its affiliate, Crescent Petroleum, have the rights to exploit Khor Mor and Chemchemal, two of the biggest gas fields in Iraq.

No group claimed responsibility, but armed groups that some Iraqi officials say are backed by Iran have claimed similar attacks in the past.

A source with knowledge of the matter also said there was no damage or impact on operations as a result of the attack and two people were treated for minor injuries.

Two security sources told Reuters earlier that a Katyusha rocket, fired from a multiple rocket launcher and first used by the Soviet Union in World War Two, hit the headquarters of Dana Gas in the Iraqi province of Kirkuk injuring three people.

In March, Iran Revolutionary Guards attacked the capital of the Kurdish region with a dozen ballistic missiles in an unprecedented assault on the capital of the autonomous Iraqi Kurdish region that appeared to target the U.S. and its allies.

At least three other attacks have targeted oil refineries in Erbil since the March attack, but no group has claimed responsibility.