Somaliland claimed independence from Somalia in 1991, and has been largely peaceful while the rest of the country has grappled with three decades of civil war, but its leadership has failed to gain widespread international recognition.
In a statement Somalia's oil ministry said it "categorically rejects Genel Energy plc's claim to own petroleum rights in Somalia's northern regions and calls upon Genel Energy plc to cease its illegal claim to own petroleum rights."
The oil ministry said it was the only institution legally authorised to grant permits in Somalia.
"Any authorisation granted in violation of Somalia's laws and regulations is unlawful and would be considered null and void," the oil ministry said.
