Morocco has accused Algeria of leaking classified government documents relating to the Western Sahara, escalating tensions as the US oil company Kosmos Energy prepares to drill its first exploratory well in the disputed territory.

Speaking on 11 Thursday Foreign Minister Salaheddine Mezouar said “the leaking of classified documents belonging to Moroccan officials was carried out by Algerian secret services”.

He also said that Morocco would “present arguments and evidence that prove Algeria’s involvement in fuelling the conflict over the Moroccan Sahara”.

Some of the documents released in the leak suggest that Moroccans bribed diplomats and foreign journalists to publicly support Morocco’s position in the dispute over its claim over the Western Sahara, thought there are doubts about authenticity.

The Moroccan government has refused to confirm or deny whether the documents are genuine, and the French journalist Jean-Marc Manach has said that his research indicated that some of the documents have been manipulated.

“The analysis of hundreds of documents posted by the mysterious whistleblower… reveals that this operation, according to the best rules of the genre, skillfully blends authentic and manipulated documents,” he said.

The deteriorating relationship between Morocco and Algeria comes as Kosmos Energy is preparing to drill in the disputed area.

Kosmos has said that it will start drilling offshore in the Cap Boujdour area of Western Sahara in December.

Kosmos acquired the licence for Cap Boujdour in 2011 and holds a 55 per cent participating interest in the concession, which covers 7.3 million acres.

The basin is the last undrilled Cretaceous basin along the Atlantic Margin, and Kosmos says it may hold as much as a billion barrels of crude.

Kosmos’ first well is expected to be drilled in about 2,050 metres of water to a planned total depth of about 6,500 metres.