In Sevastopol harbour the Ukrainian Navy's command ship Slavutych is ready to repel boarders.
Armed marines in body armour patrol the deck, mattresses are piled over railings to frustrate grappling hooks, and firehoses dangle at the ready.
With gangplanks pulled up, the only way the crew can receive gifts of cigarettes and tea from family and friends is via a makeshift pulley system running from the stern to the quayside.
Like their army and airforce colleagues on shore, the sailors on board the Slavutych and the corvette Ternopyl, both moored at the Ukrainian base in Sevastopol harbour, have for nearly a week been locked in a strange battle of nerves with surrounding Russian troops.
But judging by the Ukrainian navy's latest public statement, the crews don't find being blockaded by Russian troops and ships half as irritating as Moscow's refusal to admit what is happening.
After Vladimir Putin insisted in a press conference on Tuesday that the "men in green" who have occupied Crimea are local self defence forces, the navy fired an answering volley, "Based on [yesterday's press conference], we feel qualified to accused the President of the Russian Federation of blatant lies," the Ukrainian Navy wrote in an official announcement released on Wednesday.
"The warships Ternopyl and Slavutych, in Sevastopol bay, are currently blockaded by vessels of the Russian Black Sea Fleet, in each of which are marine units amounting to one platoon armed with automatic weapons and the corresponding kit."
"Given Mr Putin's remark that such uniforms and equipment can be purchased at any shop, we would like to take this opportunity to ask exactly which shops, and also where in violation of Ukrainian law you can also buy automatic weapons, combat pistols, and grenade launchers," the statement read.
It is the very question most journalists in Crimea have given up any hope of hearing a logical answer to.
While there are civilian pro-Russian "self defence" units in Crimea, they are generally dressed in either mixed army-surplus camouflage or simply tracksuits or jeans. The nearest they come to an actual armed force are the rag-tag Cossack units guarding the entrance to the peninsula.
They are light years from the highly disciplined, professional soldiers dressed in recent issue Russian field uniforms, driving Russian Tigr armoured jeeps, and carrying Russian weapons who have fanned out across Crimea since last Thursday.
Crimean civilians, whether pro or anti the occupation, have no doubts about the provenance of the men in green.
Ukrainian commanders who have negotiated with their unexpected guests have described how occupation force commanders introduced themselves as officers of the Russian military.
And as the occupation drags on, even the troops on the ground are struggling to maintain the pretence that their political masters in Moscow insist on maintaining.
On Saturday the soldier commanding a squad of men outside a Ukrainian navy installation in Simferopol identified himself to the Telegraph as a member of the 810th marine infantry brigade, the unit that has guarded Russia's Black Sea Fleet base since the 1960s.
Since then, journalists from Ukrainian and foreign media, including the Guardian and the BBC, have had numerous similar conversations with Russian troops who identified themselves as such.
On Wednesday a Ukrainian journalist managed to provoke a Russian officer in Kerch into an interview in which he said "we're Russian. We're here so there aren't terrorist attacks."
But for some reason, the official line from Moscow remains that there are no Russian troops in Crimea - or that if there are, they are simply regular Black Sea Fleet forces as agreed by treaty with Ukraine.
Sergei Lavrov, Russia's foreign minister, has gone so far as to claim Moscow has no authority over the "self defence" units.
"Its complete nonsense," Sergei Shoigu, Russia's respected defence minister, said when his turn to utter the strange denial came round on Wednesday.
Russia's RT television network even broadcast a segment denouncing "mainstream media" hysteria about the invasion.
"The western media has been flooded with reports going so far as to suggest that Russia has invaded Ukraine," the presenter intoned solemnly during the piece.
The Russian troops watching over the Slavutych from a nearby cliff top on Wednesday were more disciplined than some of their other colleagues, keeping themselves to a stoic "no comment," in Russian and English when asked about their job.
"We'll take your photo though," they said, producing their own camera phones, apparently fed up of being on the receiving end of photography.
When the Telegraph volunteered correspondent's name and publication to caption the image, they said they didn't need it. "We're in the loop," they said, knowingly.
* Notícia publicada a The Telegraph. La intervenció russa a Ucraïna, com s'està veient, es condueix de forma molt més metòdica que la del 2008 a Geòrgia. Recomanem clicar a l'enllaç per veure el vídeo.