• Some believe the symbol refers to contingents assigned to Ukraine regions 
  • Others think 'Z' could stand for Ukraine president Volodymyr Zelensky
  • However, the letter 'Z' doesn't actually exist in Russia's Cyrillic alphabet

Two days ago, the world witnessed Russian troops and tanks moving toward Ukraine’s vast borders for a possible invasion. But, what intrigued military experts is the mysterious "Z" symbols painted on Russian tanks and fuel trucks.

Numerous chilling theories are now doing the rounds on social media about the ominous "Z" symbol pained on the military hardware, reported Daily Beast.

While some believe the symbol refers to contingents assigned to Ukraine regions, others think "Z" could stand for Ukraine president Volodymyr Zelensky.

According to Bellingcat reporter Aric Toler, his group has been monitoring Russian military symbols for the last eight years, but they have "no idea what they [the Zs] are" and haven’t seen them before. "So, assume the worst, I guess/fear," he tweeted.

Russian Military analyst Rob Lee has a different theory. He believes the symbol may refer to contingents assigned to Ukraine regions. "It appears Russian forces near the border are painting markers, in this case 'Z,' on vehicles to identify different task forces or echelons," he posted on Twitter.

A few others think it hints at the "Zorro squad," while a more plausible theory is that the "Z" helps the Russians tell their own vehicles apart from their enemies. This was apparently a practice employed by the Allies in World War II to reduce the chance of soldiers firing on "friendly" forces. The U.K. and the U.S. forces too used the same method in the First Gulf War.

Reports quoting a military insider based in Kyiv said this tactic suggested that "final preparations are complete". "It's vital that any attacking force can be distinguished, particularly from the air where Russian forces will have complete control," he said.

He added that the Ukrainians have very similar tanks and vehicles and will want to reduce the risk of friendly fire.

Meanwhile, a former field intelligence officer David Kime tweeted that the "Z" stands for Zelensky and comes from Wagner Group "mercenaries" – a Russian paramilitary organization.

A few others believe "Z" represents "the point of no return." Other theories say markings could indicate vehicles allotted to a specific role or a new fighting unit.

However, what really adds to the mystery is that the letter 'Z' doesn't actually exist in Russia's Cyrillic alphabet.

Meanwhile, videos from the Russian border show Russian military vehicles heading towards the Ukrainian border. While Moscow calls it "peacekeeping" in the breakaway regions, the U.S. accused Russia of creating a pretext for war.

Russian tanks have been in Belarus for joint military exercises
Representation. Russian Defence Ministry via AFP / Handout