In the strategic Black Sea port city of Odesa, residents prepare to fend off Russian attack

When the air raid sirens go off in the Black Sea city ofOdesathese days, there are those who run for the bomb shelters and those who keep going about their business although perhaps in a slightly more subdued manner.

A Ukrainian colleague compared it to the early days of the pandemic, when streets emptied with expectations of potential disaster and fear of the unknown.

But after a while, people started to appear on the streets in greater numbers as they adapted to their changed circumstances.

After all, predictions thatOdesa'sstrategic value, as Ukraine's largest Black Sea port and home to its small navy, would make it an early target for the Russians have not come to pass.

Other cities have been bearing the brunt of those early assaults, and so buyingOdesatime.

"We understand that while ...Kyivfights, whileKharkivfights, whileMykolaivnow fights so bravely, we have this gap to prepare the city," saidIngaKordynovska, a lawyer co-ordinatinghumanitarian relief fromOdesato front-lines across Ukraine.

The shelves of bars and stalls in the trendyOdesaFood Market are now filled with medicine and warm clothes for front-line soldiers and essential supplies for people trapped by fighting.

Volunteers in high-viz vests pack boxes or tap away at computers in the market's two-tiered gallery, under a giant red dragonleft over from happier times and still hanging from the ceiling.

Kordynovskasays the horror of what's unfolded in cities likeKherson,Melitopoland especially Mariupol to the east is a powerful motivator and a unifier forOdesanspreparing their city for war.

"We see that every city where Russian soldiers came, everything was destroyed," she said."And of course even those people who say they are not [into] politics [that] it doesn't matter for us,Odesais a separate city now they understand that, no, you can't be out of this process. You can't say, 'It's not about me.'"

Odesa'had much time to prepare'

Some analysts have suggested the reasonOdesahas been spared so far aside from the strong resistance Russian forces have encountered in cities like Mariupol andKherson is because the city, founded by the RussianTsarinaCatherine the Great in 1794, holds special significance for Russian President Vladimir Putin.

Whatever the reason, authorities appear determined not to squander the time.Odesa'selegant downtown core is now a closed military zone dressed for war.

WATCH | People in Odesa, Ukraine, prepare for the possibility of a direct fight with the Russian military:

Odesa remains unscathed, but vigilant

2 years ago

Duration 2:30

Odesa, Ukraine, has been spared from any major Russian attacks so far, but residents of the major port city say that doesn't mean they can relax.

Metal anti-tank obstacles dot city streets, some so big they dwarf passersby, who appear from afar liketiny pieces caught in a giant's board game.

Odesa'sbaroque opera house is now beyond the reach of ordinary citizens, standing behind sandbags and glistening like a cake on the other side of a checkpoint.Musicians can still get through to practise, showing IDs to soldiers with their instruments slung over their backs.

Residents who haven't leftthe closed military zone are also allowed through, including 83-year-old MarkBradis, who served in the former Soviet army.

"And where can I go?" he said when asked why he hasn't left the cordoned-off area. "My wife is ill.She has Alzheimer's. I take care of her."

His outlook is bleak.

"It is impossible to defeat [Putin]," he said. "He has a lot of weapons that he has not yet used I'm afraid it could all end in a nuclear war."

Bradisasked: "Why should he occupy other people's lands? Enslave people? I can't understand. It doesn't fit in my head."

Some of the young soldiers on the checkpoints are more optimistic, insisting Russian troops will never be able to takeOdesa.

"They can try," saidIlya, a 23-year-old who preferred not to give his last name for security reasons. "Odesain my mind had much time to prepare. The city is definitely ready."

'This is a universal evil'

Local authorities are clearly working hard to keep morale high amongthe city's defenders.

In a somewhat surreal scene over the weekend, they staged a ceremony to honour members of the National Guard on the empty promenade at the top of the Potemkin Steps, immortalized in Sergei Eisenstein's 1925 filmBattleship Potemkin.

There were flags, two armoured personnel carriers and a marching band that struck up a zippy tune each time someone's name was called to receive a certificate but no public to watch and clap for them.

The formerly pro-Russian mayor,GennadiyTrukhanov, was on hand.

"I could not imagine that I would consider [Russians] our enemies," he said in an interview withCBCNews.

MostOdesansare native Russian speakers, and in the past there have been divisions over issues of Ukrainian and Russian identity in the city.TrukhanovsaysPutin'sinvasion has put an end to that.

"What politicians have failed to do in 30 years as they say, to sew Ukraine together we have succeeded today. We realized that we are all Ukrainian brothers and we have one land. It needs to be protected, and we will do so."

Trukhanov insisted "we are not relaxing."

"And I would advise European countries not to relax, either. Because this is a universal evil, a global evil, which today has shown its entire essence by unleashing a bloody war and killing civilians."

Watching Russian advances

The air raid sirens sound often inOdesain part because the city's air defence systems engage with cruise missiles launched by Russian warships stationed somewhere in the Black Sea at targets further inland.

Odesaitself has reportedly been hit by shelling only once, in a residential neighbourhood on the outskirts.

On Tuesday, though, a cruise missile hit the Regional State Administration Building inMykolaiv, another port city about 130 kilometres east ofOdesa.

So far, Ukrainian forces have managed to keep Russian troops from advancing beyondMykolaiv.

But if the Russians were able to get pastMykolaivon land, the consensus for many is that Moscow would be more likely to try landing troops nearOdesaby sea.

Some of the beaches along the southern coast have reportedly been mined by the Ukrainians in a bid to prevent any such attempt.

And along oneOdesastretch, near the now-dormant yacht club, local volunteers of all ages gather regularly with shovels to help fill sandbags, which are then trucked elsewhere for the city's defence.

Among the volunteers is Olga Hodis, a librarian in her 60s. She says it helps calm nerves to be doing something practical.

"Sitting and doing nothing is much worse. When you do something, you feel like you're being useful. Otherwise, you can read the news all the time and feel fearful and have panic attacks."

IngaKordynovska, who is co-ordinatingthe city's humanitarian hub, calls the community spirit a continuation of the 2014Maidanuprising, which led to the ouster of Ukraine's pro-Russia central government of the day.

"You know,Maidangave us great feelings of co-operation, but now, it is a hundred times more," she said.

"Now, we forget absolutely all our previous conflicts inside Ukraine. It doesn't matter with whom with power, with authorities, with business, with volunteer organizations.Everybody now really co-operates. And I think it's the main weapon in this war."