Rustam Temirgaliev, the Crimean First Deputy Prime Minister, in announcing the local parliament's shock decision to hold a vote on whether to join Russia, said the only military formations in the new republic would be Crimean or Russian.
"Any troops of a third country will be treated as illegal formations, with all the consequences that entails," he said, in what was taken as a reference to Ukrainian forces.
That poses an awkward question for men such as Igor Filomenko, 38, an aircraft engineer at the Belbek air force base. "I'm a Russian speaker. Well, I speak some Ukrainian but you know, it's rubbish," said Igor, who is in his 17th year in Sevastopol. "But does that give me some kind of loyalty to Moscow or Russia over Ukraine? That doesn't make any sense to me. I was born in the Soviet Union, I'm an internationalist."
His partner Julia, 32, is a housewife running their servicemen's flat in one of many of the Soviet-built five-storey apartment blocks.
Both of them now suspect that most people in Crimea are being asked to make an impossible choice.
"Fear. Expectation. Hope, finally, that all of this can be resolved bloodlessly," said Yulia, ticking off her feelings about seeing her husband carrying around a rifle instead of his tools. We all speak Russian anyway, but I never, ever thought that what language you speak would ever be an issue here.
"Everyone is in Crimea. On our street we've got Poles, Azerbaijanis, and Russians. There's the Tatars and also loads of Greeks in Crimea. I'm not going to say there was never any kind of disagreement, but everyone was living together peacefully."
Lena Seteznova, 48, another Russian citizen, also insists that the various ethnicities in Crimea have hitherto rubbed along just fine.
But any common ground stops there. "They're all from Western Ukraine over there," she said, nodding in the direction of the base. "They serve an illegitimate government that came to power in a coup. We see our future with Russia - we are Russian here. And there is no place here for those fascists from Kiev."