The letter Z is becoming a symbol of Russia's war in Ukraine. But what does it mean?

A serviceman waves from a military truck painted with the letter "Z" in Mykolaivka in the Donetsk region, a territory controlled by pro-Russian militants in eastern Ukraine, on Feb. 27. (AP)

Messages featuring the letter “Z” have spread widely across social media since Russia’s invasion of Ukraine. Billboards have recently popped up in Russian cities featuring the letter. Stickers have appeared on cars and commercial vehicles. Russia’s state-owned RT is currently selling T-shirts on its website in apparent support of the ongoing conflict.

But the origins of the symbol remain a mystery.

Prior to Russia’s invasion of Ukraine, the letter “Z” was seen painted on tanks as well as other military vehicles massing near the border. With both countries using similar tanks and trucks, it was originally thought this was meant to distinguish different units to help prevent friendly fire and assist with mobilization.