Bulgaria's efforts to achieve full interoperability with NATO partners pose an obstacle to a proposition likely to be made by Pakistan under which Sofia could acquire JF-17 fighters, according to IHS Jane's Defence Weekly.

The report emerged earlier this week in Bulgarian media outlets. Bulgaria is currently seeking to overhaul its aircraft fleet by replacing its outdated MiGs and Sukhois, and according to the information Pakistan wished to join the current shortlist including old F-16, second-hand Eurofighter jets, and new Gripens.

But the influential defense magazine notes Bulgaria's "status as a NATO member would not" make Pakistan Aeronautical Complex/Chengdu Aircraft Industry Corporation (PAC/CAC)'s JF-17 Thunder aircraft a suitable candidate.

The JF-17s are jointly produced by China and Pakistan and have "yet to secure" their first international customer, IHS Jane notes.

They are not "NATO-compatible" it adds, citing the example of Turkey's attempt at acquiring a Chinese missile defense system in 2013 (and the Alliance's subsequent outcry) to point out it would be "extremely difficult for Sofia" to carry out such a deal.

"Being a new and enthusiastic member of NATO, Bulgaria will be loath to place itself in a similar position, and for this reason primarily it would seem that a JF-17 buy is not likely to happen," the analysis concludes.