Gulf Keystone Petroleum (LONGKP) said today it will vigorously challenge an attempt by Excalibur Ventures to claim a 30 per cent share in its blocks in Kurdistan.
Proceedings have been launched against Iraq-focused GKP and two of its subsidiaries in London and New York.
A judge in London has already refused an application by Excalibur for a worldwide freezing injunction against Gulf Keystone's assets.
Chairman Todd Kozel said: "We believe we have very good grounds to vigorously challenge these claims in both the US and UK courts.
"We are confident of being able to defeat these claims in any legal jurisdiction and meanwhile, we remain focused on building upon our considerable operational success and continuing to prove the full value of our world class acreage."
It is understood the Excalibur action stems from an agreement dating back a number of years which was timed out well before the award of production sharing contracts in Kurdistan.
Gulf Keystone has production sharing contracts for four exploration blocks in northern Iraq.
It is currently embarking on an active appraisal and exploration drilling campaign in Kurdistan, including work to fully understand the scale of the world class Shaikan Field discovered in 2009.
Shaikan has the very real potential of being a “company maker”.
There is, however, an even greater prize if Shaikan and the adjacent projects of Sheikh Adi, Akri Bijeel and Ber Bahr turn out to be part of the same oil body.
Then GKP might then have a find on the scale of the Kirkuk to the south, which is estimated to have 60 billion barrels of oil in place, 20 billion of them recoverable.
Shares in the company, which are up 82 per cent so far this year, fell 21.5p to 163p.