Ukraine and Russia may both use unconventional warfare tactics in the ongoing war, a former CIA officer told Fox News.

Ukraine and its allies may employ cyber-tactics and continue insurgency efforts, while Russia may resort to chemical warfare to accelerate its invasion, according to Ronald D. Johnson, a retired Army colonel and former U.S. Ambassador to El Salvador.

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"It also involves a lot of other things because sometimes you're talking about a smaller insurgency force that's battling a larger, more powerful occupying force," Johnson, who spent over 20 years in the CIA as a paramilitary operations officer, said. "You’re also talking about psychological operations, you're talking about sabotage and, today, information operations, cyberattacks and even influence campaigns." 

Cyber capability will benefit the Ukrainian resistance, according to Johnson. 

"Russia can stop incoming cyber communications, but they can only do it temporarily," Johnson said. "I think it's important now when you look at today's world to even consider the power of a single person with a laptop computer and internet connectivity."

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Johnson told Fox News that this cyber power will spread messaging critical of Russian President Vladimir Putin

Unconventional warfare tactics, including insurgency, make it less likely for Russia to occupy Ukraine long-term, according to Johnson.

Civilians practice moving in groups at a military training exercise conducted by the Prosvita society in Ivano-Frankivsk, Ukraine, on Friday, March 11, 2022. (Alexey Furman/Bloomberg via Getty Images)

Civilians practice moving in groups at a military training exercise conducted by the Prosvita society in Ivano-Frankivsk, Ukraine, on Friday, March 11, 2022. (Alexey Furman/Bloomberg via Getty Images) (Alexey Furman/Bloomberg via Getty Images)

"A lot of countries in the free world and even private organizations will look for ways that they can support that insurgency or that resistance," he told Fox News.

Russia's advances have stalled recently. Western intelligence expected Kyiv to fall within 72 hours of the invasion, but the capital city still remains under the Ukrainian government's control.

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Putin "sees the threat of an insurgency and a prolonged war that could drain his resources and his people for years to come," Johnson said. He warned that the authoritarian leader may use "unconventional weapons like chemical weapons" to "accelerate the siege process."

White House press secretary Jen Psaki has similarly warned that Russia could use "chemical or biological weapons in Ukraine or to create a false flag operation using them."

The Kremlin has made unfounded claims that Ukraine, with U.S. assistance, is preparing to use chemical or biological weapons against Russian forces.