Pro-Russian rebels in Ukraine hope for support from Putin, but no such support is on the horizon. It may be weeks or longer , but one by one, the Ukrainian army is taking back rebel-controlled areas.

Next up, Donetsk: A rebel city encircled by Ukraine’s army.

A week has passed since the turning point of the Ukrainian army’s triumph in Slavyansk, 110km north, the rebels’ main stronghold in eastern Ukraine, but from which the militants fled last Saturday. Many headed to Donetsk, vowing to make a final stand.

Slavyansk fell after weeks-long siege and relentless shelling, with electricity and water turned off – for which each side blamed the other. But analysts and Donetsk residents warn similar tactics would risk too many casualties in a city nearly 10 times the size. Ukrainian officials have pledged not to bomb Donetsk, though many residents are not reassured.

“It has been a considerable achievement this week of the Ukrainian armed forces in eastern Ukraine, but the heaviest work is still to come,” says Jonathan Eyal, international director at the Royal United Services Institute, a military think tank. “Securing the large cities is a far more difficult task. The Ukrainian forces will have much less to rely on in terms of sympathetic infrastructure. The police, for example, are locally recruited, and more pro-Russian.”

The rebels, meanwhile, seem to be pinning hopes on help arriving from Russia, which still has a big military presence less than 100km away at the border.

As the fighting rages, Ukraine reported 23 of its servicemen killed on Friday, including 19 in a missile attack near the border. A day earlier Kiev said it had killed more than 50 rebels in airstrikes near Donetsk.

In the broader Donbass, Ukraine’s industrial heartland of which Donetsk is the centre, hundreds have died. US agribusiness giant Cargill closed a $50m sunflower seed processing factory after it was occupied by armed militants.

Armed rebels – some locals, others from Russia – occasionally roam Donetsk on foot, or roll by in tanks and trucks.

To exit the city, cars must pass through armed separatist checkpoints. “Be careful, the Fascists are a few kilometres down,” a rebel guarding the road south said, referring to Ukraine’s approaching military – widely portrayed by Russian television since the ousting of Ukraine’s president Viktor Yanukovich – as ultranationalists.

Down the road, the commander of a Ukrainian military squad asks: “What’s it like up there? Are there many of them? Are they locals or fighters from Russia?”

Ukrainian officials say they aim to blockade Donetsk, forcing separatists to surrender or retreat. A military spokesperson talked of a “surprise” for the separatists, But it was unclear if that meant incursions into the city, which could involve bloody urban warfare – giving Russia a pretext for an invasion to protect the region’s large Russian-speaking population.

Separatists appeared to be entrenching themselves for potential guerrilla warfare. Kiev accuses them of using Donetsk as a human shield.

“We are preparing our defences,” Igor Strelkov, the separatists’ military commander, told a Thursday press conference in the city’s government administration building, now surrounded by separatists with Kalashnikovs and shoulder-fired rocket launchers. It was his first public appearance since fleeing from Slavyansk with his men.

What Now?

The Ukrainian army is about to retake Donetsk. They can take it quicker by brute force, or it may take weeks or months to starve it out.

In spite of pledges to not bomb Donetsk, the government has not shown the least bit of patience or willingness to negotiate. They offered a ceasefire – but only if the rebels laid down their arms. Ceasefire on those terms means surrender, and the rebels refuse.

One way or another, sooner or later, Ukraine will retake Donetsk. Then what? Scars and resentment will linger for years, even in the best of cases. And if Ukraine backs down on promises to give regions more autonomy, prolonged guerrilla warfare is a possibility.

Mike “Mish” Shedlock