The mayor told BNS the conversation took place during the ambassador's recent visit to Vilnius Municipality.
"Just by the way, he asked whether I'd been to Crimea and invited me to come and see if everything was fine. I understand it was a coded and very clear message. These things have to be taken seriously," the mayor told BNS.
"I think it was important remind him that he was completely wrong by inviting me to an occupied territory. My response was that I would love to visit Crimea once again but after being invited not by him but by the Ukrainian ambassador," Šimašius said.
"He said I might have to wait long but I expressed hope that it won’t take long, and even if I do have to wait, I will," the Vilnius mayor said.
Russia annexed Crimea in March 2015, leading to Western sanctions against Moscow.