The progress of Russian forces in Ukraine may be limited by the high price they have paid

But capturing the last pocket of Ukrainian resistance in Luhansk province came at a high price. The main question now is whether Russia can muster enough forces for a new offensive, which would ensure the capture of the Donbass region and other Ukrainian territories.

“Yes, the Russians have taken the Luhansk region, but at what cost?” says Oleh Zhdanov, a military analyst in Ukraine, noting that some of the Russian units involved in the battle lost more than half of their soldiers.

Even President Vladimir Putin admitted on Monday that the Russian forces involved in the fighting in Luhansk should “rest and strengthen their combat capacity”.

This raises the question of whether Russian forces and their separatist allies are ready to advance further into Donetsk, the other province that makes up the Donbass region. Observers estimate that in recent weeks, Russia controlled about half of Donetsk and that the front line has not changed much.

What will happen in Donbas can determine the further course of the war. If Russia succeeds there, its forces can be moved to take other territories and dictate the terms of a peace agreement. If, on the other hand, Ukraine manages to hold off Russian forces for an extended period, then it can rebuild the capabilities it needs for a counteroffensive.

Exhausting Russian forces has long been the plan of the Ukrainians, who were less heavily armed at the start of the conflict but hoped that Western arms supplies would shift the balance of power.

The Ukrainians are already effectively using heavy artillery and advanced missile systems sent by the United States and other Western allies. Although arms supplies will continue, Ukrainian forces have said they are at a major disadvantage.

Ukrainian Defense Minister Hanna Malyar recently said that Russian forces were using nearly 10 times more ammunition than the Ukrainian military.

After failing to quickly seize control of Kiev in the first weeks of the war, Russian forces withdrew from much of northern and central Ukraine and turned their attention to the Donbass, a mining and factory region where separatists-backed from Moscow, have been fighting against the Ukrainians since 2014.

Since then, Russia has embraced a slow-and-steady approach that has allowed it to capture the last few Ukrainian strongholds in Luhansk in recent weeks.

While Ukrainian officials have acknowledged that their troops have withdrawn from the town of Lysychansk, the last center of their resistance in Luhansk, the president’s office said on Tuesday that the army was still defending small areas in the province.

Analyst Zhdanov predicts that Russian forces are likely to rely on their firepower to “implement the same scorched earth tactics and bomb entire cities” in Donetsk. On the same day that Russia claimed to have taken Lysychansk, new artillery attacks were reported in Donetsk.

But Russia’s approach is not without its drawbacks. Moscow has not disclosed the number of casualties, since it said around 1,300 soldiers were killed in the first month of fighting. Western officials say that even this figure did not reflect the real losses. Since then, Western observers have noted that the number of Russian forces engaged in fighting in Ukraine has dwindled, reflecting heavy casualties and the Kremlin’s failure to replenish their ranks.

Limited force numbers have forced Russian commanders to eschew ambitious efforts to encircle large areas in the Donbas, opting for smaller maneuvers and relying on heavy waves of artillery bombardment to slowly force the Ukrainians to to withdraw.

The military has also relied heavily on the separatists, who have staged several rounds of mobilization, and Western officials and analysts have said Moscow has increasingly engaged private military contractors. It has also tried to encourage Russian men who have already completed military service to re-enlist, although it is unclear how successful it has been.

While Russian President Putin has so far not announced a widespread mobilization, which could fuel social unrest, recently proposed legislation suggests Moscow is looking for other ways to supplement its military forces. The bill would allow new recruits, who are conscripted for a year and barred from combat, to immediately change their status and sign contracts to become professional soldiers. The bill was canceled amid strong criticism.

Some Western officials and analysts have argued that the drawdown is so severe that it could force Moscow to suspend its offensive later in the summer, but the Pentagon has warned that even as Russia rapidly deploys forces military and supplies, it still has abundant resources.

US Director of National Intelligence Avril Haines said President Putin appeared to accept the slow pace of progress in Donbas and now hopes to win by destroying Ukrainian forces with battlefield experience.

“We believe that Russia thinks that if they are able to really defeat one of the most capable and well-equipped formations in the east of Ukraine … it will bring about a decline in the Ukrainian resistance and that may give them (the Russians) opportunities bigger,” Ms. Haines said.

If Russia wins in Donbas, it could go on to occupy the southern Kherson region and part of neighboring Zaporizhzhia in an attempt to eventually cut off Ukraine from its Black Sea coast to the Romanian border. If successful, this would deal a crushing blow to the Ukrainian economy and also create a corridor to Moldova’s breakaway Transnistria region, where a Russian military base is located.

But this is by no means certain. Mykola Sunhurovsky of the Razumkov Center, a Kyiv-based think tank, predicts that increasing supplies of Western heavy weaponry, including multiple HIMARS missiles, will help Ukraine change the course of the war.

“The arms supplies will allow Ukraine to launch a counteroffensive in the south and fight for Kherson and other cities,” Mr. Sunhurovsky said.

But Ukraine has also faced massive losses of personnel: up to 200 soldiers a day in recent weeks of heavy fighting in the east, according to officials.

“Overall, the local military balance in Donbas favors Russia, but long-term trends still favor Ukraine,” writes Michael Kofman, an expert on the Russian military and program director at the Virginia-based CNA Institute. “However, this assessment is conditional on sustained Western military assistance and is not necessarily predictive of outcomes. This is likely to be a protracted war,” he said.

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