U.S. Army Chief Of Staff Gen. Ray Odierno speaks to the media during last briefing at the Pentagon before he retires, August 12, 2015 in Washington, D.C.
Mark Wilson/Getty Images
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(L/R): Head of Dutch Military Intelligence and Security Service Onno Eichelsheim, Minister of Defence Ank Bijleveld and British ambassador Peter Wilson attend a press conference of the Dutch Military Intelligence and Security Service (MIVD) at The Hague, The Netherlands, on October 4, 2018. - Dutch intelligence thwarted a Russian cyber attack targeting the global chemical weapons watchdog in April and expelled four Russian agents, the government said. The Russians set up a car full of electronic equipment in the car park of a hotel next to the Organisation for the Prohibition for Chemical Weapons in The Hague in a bid to hack its computer system, it said. (Photo by Bart Maat / ANP / AFP) / Netherlands OUT        (Photo credit should read BART MAAT/AFP/Getty Images)
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(L/R): Head of Dutch Military Intelligence and Security Service Onno Eichelsheim, Minister of Defence Ank Bijleveld and British ambassador Peter Wilson attend a press conference of the Dutch Military Intelligence and Security Service (MIVD) at The Hague, The Netherlands, on October 4, 2018. - Dutch intelligence thwarted a Russian cyber attack targeting the global chemical weapons watchdog in April and expelled four Russian agents, the government said. The Russians set up a car full of electronic equipment in the car park of a hotel next to the Organisation for the Prohibition for Chemical Weapons in The Hague in a bid to hack its computer system, it said. (Photo by Bart Maat / ANP / AFP) / Netherlands OUT (Photo credit should read BART MAAT/AFP/Getty Images)
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Bowtie TV
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SALISBURY, ENGLAND - JULY 05:  A police officer stands by a cordon in place at Queen Elizabeth Gardens in Salisbury after a major incident was declared when a man and woman were exposed to the Novichok nerve agent on July 5, 2018 in Salisbury, England. The couple, named locally as Dawn Sturgess 44, and Charlie Rowley, 45 were taken to Salisbury District Hospital on Saturday and remain there in a critical condition. In March Russian former spy Sergei Skripal and his 33-year-old daughter Yulia were poisoned with the Russian-made Novichok in the town of Salisbury. British Prime Minister Theresa May has accused Russia of being behind the attack on the former spy and his daughter, expelling 23 Russian diplomats in retaliation. (Photo by Jack Taylor/Getty Images)
Jack Taylor/Getty Images
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(CNN) —  

The outgoing Army chief of staff said Wednesday that Russia posed the “most dangerous” threat facing the United States today, thanks to its “sophisticated” operations in Ukraine.

Gen. Raymond Odierno, who is leaving his post, estimated that only a third of U.S. brigades are capable of operating at the level of the hybrid warfare Russia is undertaking there. And he worries that Russia could next intervene in NATO allies like Latvia or Estonia.

“They are more mature than some other of our potential adversaries, and I think they have some stated intents that concern me in terms of how the Cold War ended,” Odierno said of Russia when asked by CNN. “They have shown some significant capability in Ukraine to do operations that are fairly sophisticated, and so, for me, I think we should pay a lot of attention.”

Odierno explained that he’s concerned that Russia underestimates the extent to which NATO partners would defend the Latvians and Estonians, a miscalculation that could lead to conflict. The solution, he argued, would be to increase response capabilities in order to deter any possible Russian aggression.

“We have deterrent there and I think we’re doing a good job with that,” he said. “What we have do in the next several years is continue to increase that so the risk goes up for anybody who might consider operations in Eastern Europe.”