In January, US oil giant Exxon Mobil signed a deal with Ghana to explore for oil in the Deepwater Cape Three Point offshore (DWCTP) oilfield.
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The signing followed direct negotiations between Ghana and Exxon Mobil without an open competitive tender due to the nature of the field, where the depth ranges from 2,000 to 4,000 meters, Ghanaian officials said, according to Reuters.
Speaking to RT International following a protest led by the Ghana First Patriotic Front against the military cooperation deal, Mr Horne said Exxon Mobil is concerned about its investment in West Africa and therefore will desire an enhanced US military role in the Ghana.
He said: "Keep in mind that the US oil giant has been exploring offshore oil from Ghana and reportedly have discovered many finds of petroleum.
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"And I dare say these US oil giant are also concerned about protecting their investment in West Africa. And therefore they would also demand, desire an enhanced and increased US military role."
The military agreement gives the US military "unimpeded" access to Ghana, immunity for US soldiers, access to runways, tax exceptions, radio frequency among others.