Mr Panetta took the opportunity to announce a delayed timeframe for planned cuts to the Lajes Air Base in Portugal's Azores, a group of nine volcanic islands located almost 1, 000 miles (1, 600km) west of the Iberian peninsula.

BBC: Leon Panetta makes final international trip to Europe

On Sunday, the junta closed all Guinea-Bissau's air and sea borders after Portugal announced it was sending two navy ships and a military plane for a possible evacuation of its nationals.

BBC: Guinea-Bissau junta agrees pact with some parties

However, both pilots of an Air Comet flight from Lima, Peru, to Lisbon, Portugal, sent a written report on the bright flash they said they saw to Air France, Airbus and the Spanish civil aviation authority, the airline told CNN.

CNN: Brazilian air force says debris was not from Air France crash