Speaking to the UK's Daily Telegraph newspaper, the former Danish Prime Minister said:
“There is a high probability that he will intervene in the Baltics to test NATO’s Article 5... Putin knows that if he crosses the red line and attacks a NATO ally, he will be defeated. Let us be quite clear about that. But he is a specialist in hybrid warfare.”
Article 5 is NATO's collective defense agreement which is intended to mean that an attack on one member state is treated as an attack on all.
However, the 'hybrid' model favored by Russia's current government, which uses tools such as cyber-attacks, propaganda campaigns and the use of so-called "little green men" and military equipment bearing no insignia attempts to muddy the waters of what constitutes an attack.
Rasmussen was a frequent visitor to the Baltic states during his stint as NATO Secretary General from 2009-2014, most notbly during the Steadfast Jazz drills of 2013 which rehearsed a NATO response to an invading neighbor.
Responding to Fogh Rasmussen's comments, Latvian Foreign Ministry spokesman Martins Dregeris told LSM:
"Latvia belongs to the most powerful military alliance in history. I would like to stress that the current NATO Secretary General recently said there is no immediate threat.
"NATO will defend any ally against any external threat, as the Secretary General has repeatedly said.
"We are aware of the potential risks of 'hybrid' warfare, which is why we are working closely with our NATO partners to counter this threat."
Estonian Prime Minister gave ERR News a similar response saying:
“Hybrid war is not a new or surprising type of war – not in the world, not in Estonia and not in Russia. Estonia has considered it and planned its national defense intelligently, by increasing our independent capabilities and improving relations with allies against any would-be aggressor.”