Ukrainian media said the subject of the deal could be Soviet-designed T-72 tanks. "The deal was signed three days ago. It is one of the biggest deals for the past 15 years," said the official, speaking in Kiev and declining to be named.

The agreement comes weeks after the Horn of Africa nation signed a deal to buy unmanned aerial vehicles from Israeli company BlueBird Aero Systems for surveillance operations, according to separate Ukrainian media reports.

Authorities in Addis Ababa were not available for comment on either case. Addis Ababa has been at loggerheads with Eritrea since their 1998-2000 border war which killed around 80,000 people, and both sides have amassed large amounts of troops along their disputed frontier ever since.