Russia is not as "strong" as it appears and could "collapse", Ukrainian partisans told the Express.
Atesh is a partisan group made up of Crimean Tatars and Ukrainians, that is operating behind Russian lines in the occupied territories.
Meaning "Fire" in the Crimean Tatar language, the group was formed in the immediate aftermath of Vladimir Putin's full-scale invasion of Ukraine in 2022.
They have inflicted major blows against the Kremlin's army, playing a key role in the destruction of the headquarters of Russia's Black Sea Fleet in September 2023.
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A Ukrainian missile strike destroyed the command post, killing 34 officers and injuring more than 100 people in one of the deadliest attacks on Russia's navy.
Over the course of last year, Putin's army has regained the initiative on the battlefield, making their fastest territorial gains since the start of the full blown war.
Russia's generals have leveraged their numerical superiority in both weapons and manpower to make sweeping advances in the Donetsk region, and are threatening to capture the key strategic city of Pokrovsk.
Many Western experts now fear that Ukraine cannot win the war and needs to sue for peace.
Atesh rebels, however, told the Express, that Russia was vulnerable and must be decisively defeated.
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"Russia is not as strong as it seems," they said. "Corruption, demoralisation of the army, sanctions and the resistance of Ukraine make it vulnerable.
"It tries to convey stability, but it may collapse one day, as happened earlier in history."
They added: "People must understand that unpunished evil will definitely return and repeat its aggression with even greater force.
"It is also important to realise that by helping Ukraine, they are primarily investing in their own security."
The group provided insights into some of the operations they have carried out in the past and the dangers of operating behind enemy lines.
Recalling a mission they dubbed the "Ukrainian Night", they explained how a local resident of a village helped them punish Russian soldiers for abusing the residents.
A Russian unit had recently moved into the village of Velikiye Kopani in the Kherson region, and soon began a campaign of fear and repression.
"One of the villagers joined the ATESH lavas to punish them," they explained. "That night, two Russian servicemen were killed by our agent. The agent shot them while they were drunk and under the influence of drugs. After that, he was able to hide the weapon and leave the village by the morning."
They continued: "There were quite a few similar episodes during that period. We actively targeted collaborators and representatives of the occupation administrations. Some of them were eliminated, and some survived."
Atesh agents risk torture and death if they are captured by the Russians and say it is becoming increasingly more difficult to carry out operations.
"The heightened counterintelligence regime poses challenges to our work," they said.
"Sometimes it's difficult to even deliver explosives. Moreover, Russian special services are constantly trying to penetrate our ranks."
The group says its members are motivated by a desire for revenge against the Russians "for their lost loved ones and for those held hostage by the Putin regime."
They claim to have representatives right across Russia, including in the major cities of Moscow and Saint Petersburg, and say they are forging alliances with other Tatar ethnic minorities inside the country.
"We feel the support of representatives of the Turkic and Caucasian peoples in Russia," they said. "Therefore, we have many tools to strike at Putin's war machine."