Russia is not bereft of friends in the Balkans, Lamrani said, pointing to Serbia in particular.
A 2016 coup attempt in Montenegro is believed to have been a Russian effort to keep the Balkan country from joining NATO, which it did the following year. A Montenegrin court ruled this year that Russian military intelligence agents coordinated the attempt from Serbia and were allowed to leave by Serbian authorities.
Moscow has sought to keep others out of NATO, including Serbia, which already buys Russian weapons and may buy more.
Southeastern Europe has been a concern for NATO for some time and for multiple reasons.
"In the '90s it was the instability ... and the conflicts there," Lamrani said. "Obviously now it's a concern because that's where Russia has the most influence in" Europe.
"There's been concern in NATO that Greece has some close ties with Russia ... Now you're talking about Turkey being in that same bucket while ironically Greece is shifting back to NATO," Lamrani added.
"There's definitely been longstanding concern with the southeastern flank, and now especially it's definitely the most troublesome in terms of the front line with Russia."