Estonia may be one of NATO's smallest members, but its air force commander had the strongest words for Russian aggression in Ukraine at a gathering of allied military leaders.

Russian President Vladimir Putin's "war against Ukraine did not really come as a surprised to us," Col. Jaak Tarien, commander of the Estonian Air Force, told an audience at the U.S. Air Force Association's 2014 Air and Space Conference.

Speaking with a group of NATO military leaders, Tarien reminded how Soviet Russia launched a similar operation in Estonia in 1924.

"Soviet Russia sent infiltrators to our young republic. They tried to rally local people to demonstrate against our government," he said.

The Estonian people did not want to go along.

"So on the night of Dec. 1, they tried to take over key government buildings and take over the post office was the key to their success because then they were supposed to send a telegraph to Moscow asking, in the name of a newly formed government, to send in assistance troops which were already forming up on our eastern border," Tarien said. "Sounds familiar doesn't it?

The Estonia people did not allow this to happen.

"Now Putin is not relying on people in Ukraine, now he is sending in what I call his road circus," Tarien said, describing how some of the protestors in Ukraine have turned out to be citizens of Moscow.

One of Putin's most successful tactics, Tarien maintains, is his use of "little green men," or large numbers of what appear to be a well-armed private army. They were armed with Russian uniforms, weapons and communications gear, but Putin said they were not his men, Tarien said.

This caused NATO to hesitate, he said.

"Putin's use of little green men really through a wrench into our western decision making cycle," Tarien said. "I'm not saying we should have launched a military response; Ukraine is not a NATO nation.

"But we could not come up with any decision for a long time. We couldn't agree with what is going on. Mr. Putin saw a weakness in our decision making cycle. Let's not let him exploit that again."

Tarien maintains that Putin has said the security architecture of Europe is a Cold War relic and needs to be changed.

"I may be the youngest air chief in NATO, but I'm old enough to have gone to school in Soviet-occupied Estonia and heard the Soviet rhetoric that the biggest threat to world peace is American imperialism and NATO is merely their tool … So when Mr. Putin says rearrange the security architecture of Europe he means Europe without America, Europe which he can dominate," Tarien said.

So if Putin sends his "road circus into a NATO country" -- NATO officials know "NATO will respond, but does Mr. Putin know NATO will respond? Is our message loud and clear enough?" Tarien asked.

-- Matthew Cox can be reached at matthew.cox@monster.com