The remarks come more than nine months after Russian President Vladimir Putin launched the Ukraine invasion in February, hoping for a quick win against its much smaller neighbour.

However, Ukraine’s defense efforts, boosted by Western humanitarian and military aid, have blunted Moscow’s military gains. Putin’s troops continue to struggle to achieve substantial goals even though Russia illegally annexed four Ukranian regions they don’t have total control over .

Throughout the war, concerns have emerged about whether Putin would order the use of nuclear weapons if he feels he has no other way to win the war or if the war grows into a greater conflict with the North Atlantic Treaty Organization (NATO).

Alexander Khodakovsky, the commander of Russia’s Donetsk militia, pointed to nuclear weapons as one way Russia could win the war during an appearance on state TV.

He said Russian military authorities realize their resources “have their limits,” suggesting they may have to turn to nuclear weapons to defeat Ukraine.

“Everyone realizes that the next spiral of escalation can only be the nuclear stage of war,” Khodakovsky said.

Russia could deploy nuclear weapons if NATO crosses “certain boundaries” and becomes “directly involved” in the military conflict, Khodakovsky said.

So far, the West has limited its involvement in the war to supplying Ukraine humanitarian and military support, as sending troops would likely lead to an escalation of the war.

He admitted that Russia lacks the ability to combat against the entirety of NATO using conventional weapons.

“We don’t have the ability—we’re a country which is now fighting the entire Western world, and we don’t have the resources to defeat the NATO bloc with conventional means,” he said. “But we have nuclear weapons for that. We built them specially for such situations. That is why there is only one option.”

Despite Khodakovsky’s remarks, NATO has not indicated any plans to begin direct involvement in the Ukraine war.

In September, Putin issued a threat against countries he believes are trying to “blackmail” him with their nuclear weapons, an apparent jab at Western countries, as he ordered a partial mobilization of troops to escalate the war.

“Those who are trying to blackmail us with nuclear weapons should know that the winds can also turn in their direction,” Putin said.

However, in October, Putin downplayed the possibility of using nukes, saying that there is “no point in that, neither political nor military,” according to the Associated Press.