Updated

NATO is launching its biggest military exercise in 13 years, mobilizing 36,000 soldiers, sailors and airmen from more than 30 countries to test the alliance's ability to respond to new security threats.

NATO Deputy Secretary-General Alexander Vershbow told the opening ceremony Monday that the Trident Juncture exercise will demonstrate that NATO "can deal with everything from conventional military engagements to more subtle hybrid warfare techniques and propaganda."

Vershbow said the geopolitical situation is considerably more unstable than the last time such large-scale exercises were held during the Cold War, citing Russia's annexation of Crimea, support of eastern Ukrainian separatists and the spread of extremist groups into Libya and Syria.

The exercise runs through early November and extends through Spain and Portugal and adjacent waters.