A group of senior Gabonese military officers appeared on national television in the early hours of Wednesday and said they had taken power after the state election body announced President Ali Bongo had won a third term.
The signs of a coup in Gabon come just weeks after members of the presidential guard in Niger seized power and established a junta.
Speaking at a meeting of EU defence ministers in Toledo, Borrell said “If this is confirmed, it is another military coup which increases instability in the whole region.
“The whole area, starting with Central African Republic, then Mali, then Burkina Faso, now Niger, maybe Gabon, it’s in a very difficult situation and certainly the ministers … have to have a deep thought on what is going on there and how we can improve our policy in respect with these countries
“This is a big issue for Europe,” he added as quoted by Reuters.