Tanzania, Feb. 16 -- Dar es Salaam. Frustrations around the dollar supply have continued to emerge, with oil marketing companies revealing how they battle the shortage of foreign currency at their own cost.

A leaked letter shows that the oil suppliers, through their association, were seeking an audience with the Ministry of Energy to discuss the situation in which the companies said they were selling fuel at a loss.

The oil marketers said they have been buying dollars at a higher rate than that of the central bank, even contrary to the rate displayed by commercial banks.

They raised concerns over the sustainability of the business, revealing that they are currently grappling with significant losses attributed to a scarcity of dollars a...