There has long been a controversy about the extent to which the Soviet Union and Cuba supported the Ethiopians during their thirty year war against Eritrean liberation movements.
This document – from the CIA archive – dated 17 March 1978, indicates that the CIA believed the Soviets were offering advice and that its generals were helping plan an offensive against the Eritrean liberation movements.
But what of the Cubans? Apparently there were fewer than 100, working for the Ethiopians in Eritrea.
But perhaps their role was more active than had previously been suggested. This – of course – assumes that the CIA assessment is correct, which it may not be.