PEREVALNYE, Ukraine (AP) -- In the eastern reaches of Ukraine's Crimean Peninsula, witnesses report advanced Russian surface-to-air missiles being offloaded and readied for movement. At a base near the naval port of Sevastopol, an air force commander takes to YouTube to appeal for clear orders of engagement with the Russian forces who have occupied much of his base. In a naval base near regional capital Simferopol, a commander reports feeling like a hostage, and fearing what will come in the next few days.
On the eve of Sunday's referendum on whether the Black Sea peninsula should break away from Ukraine and join Russia, Crimeans of all ethnicities waited with deepening anguish and fear about the vote that at best, will yield months or years of uncertainty, and at worst, will spark war.
Among those facing the greatest and most fraught uncertainty were Ukraine's military forces on the peninsula, who have been hemmed in by heavily armed Russian troops and warned by the region's pro-Russian leader that they would be considered "illegal" if they didn't surrender.
With the new government in Kiev struggling to respond to a threatened Russian invasion in the east, build international support and stave off economic disaster, soldiers and sailors have lamented openly that they don't know what they're supposed to be doing. And, more importantly, what they're going to do if shooting breaks out.
Russia effectively took control of Crimea, where it has a large naval base, late last month after Moscow-friendly President Viktor Yanukovych fled the country in the wake of months of protests. The Kremlin says he was the victim of a coup and refuses to recognize the authorities who took over.
The head of Crimea's unrecognized Russian-backed government, Sergei Aksyonov, has said Ukrainian solders will be allowed to surrender peacefully, leave Crimea altogether or resign from the armed forces.
In a message on Twitter, he warned that Ukrainian units that refuse to swear allegiance to the new Crimean authorities after Sunday's referendum would be considered "illegal armed formations."
Ukrainian officials have said more than 20,000 Russian troops are in Crimea. Many are believed to be under the command of the Black Sea Fleet, which is based in Sevastopol under a lease deal with Ukraine.
Against this backdrop, Ukraine's outmatched armed forces have been stuck in the middle, harassed and blockaded in bases by masked gunmen and Russian soldiers wearing no identifying emblems, but often driving military trucks bearing Russian license plates. Ukrainian officers and servicemen have complained about not only being outgunned, but also about having no clear direction or orders from Kiev, where a new government is struggling to take shape and to respond to the Russian threats.
In the video made earlier this week, Col. Yuly Mamchur of the 204th Tactical Aviation Brigade sits with four other officers and appeals for direction from his commanders: the Belbek military airfield he commands is under pressure from Russian forces that have cordoned it off, and he fears his men may have to start shooting.
"Each day, we receive ultimatums of an increasingly harsh nature from the armed forces of the Russian Federation. In the interest of averting the possibility of armed clashes I appeal to you in the nearest possible term to issue clear instructions to commanders," Mamchur says in the video posted to YouTube. "If no such corresponding order is issued, we will be forced to act under the general orders of the Ukrainian armed forces and open fire. We are ready to fulfill our orders to the very end."
The video appeal by Mamchur was echoed Friday by a group of senior generals, including several former defense ministers, who released an open letter to Russian President Vladimir Putin to withdraw Russian forces from Ukraine.
"Morally, Ukrainian soldiers are not yet ready to fire at Russian soldiers. Further escalation of unlawful actions of Russian troops in Crimea may change this situation drastically," the letter said. "The mothers of our soldiers will never forgive us if the blood of their sons is spilled."
A spokesman for the Ukrainian military in Crimea, Vladislav Seleznyov, said witnesses in the eastern port of Kerch, which is separated from Russia by the narrow Straits of Kerch, had seen more than a dozen S-300 surface-to-air missile launchers at the railway station. Ukrainian social media sites are crowded with photos and video of Russian artillery being moved along Crimean roads and Russian radar stations being erected on hilltops.
Outside the Ukrainian 36th Coastal Defense Brigade base at Perevalnye, a Cold War-type atmosphere -- tense but controlled -- prevailed this week.