Tullow said earlier this month that an investigation by the US Department of Justice and the Securities & Exchange Commission into Hyperdynamics' activities off Guinea had made it impossible for to proceed with drilling until the issues were resolved.
Hyperdynamics said the force majeure to suspend exploration plans was asserted "without advance notification or discussion".
The company said it "believes Tullow's unilateral actions are unwarranted and untimely, and that a force majeure event has not occurred", adding that it has communicated its response to the government of Guinea and to Tullow.
"Hyperdynamics
