As Russia relies on the formidable destructive power to advance a mile or two a day into eastern Ukraine, Ukrainian soldiers fighting some 400 miles to the south are working steadily to clear Russian frontline positions across an expanse of steppe and swamp.

Fighting is fierce on both fronts, and how the two campaigns unfold is critical to understanding the war’s situation, as concern grows that a drawn-out conflict will bring new economic costs to Ukraine’s allies.

Russian President Vladimir Putin said last week that he believed he would wait for the West to come out. While the Russian leader rarely acknowledges Russian losses or defeats, military analysts said the beatings to his army raised questions about whether he could continue large-scale offensive operations after the end of his campaign to capture Luhansk province.

Russia has devoted the bulk of its combat forces to the capture of Lysichansk, the last urban center in Luhansk still under the control of the Ukrainian government, and could fall any day.

Russia has sent thousands of additional troops to the east in recent weeks to reinforce its offensive on neighboring Donetsk province, where it will likely attempt once again to conquer heavily fortified Ukrainian positions with its large arsenal of artillery, missiles and air power, even if… The ground forces are dwindling.

How much each army has diminished after more than four months of war is an open question. Kyiv releases only public estimates of its losses, and Moscow says almost nothing.

British Defense Secretary Ben Wallace said last week that 25,000 Russian soldiers had been killed since the war began. This figure, which cannot be independently confirmed, is the highest estimate given by a senior Western official. The Ukrainian government has acknowledged that it has suffered heavy losses, with hundreds of casualties every day.

Even if Russia managed to penetrate deeper into Donetsk, its army struggled to maintain progress along multiple lines of attack in different parts of the country. Roughly the size of Texas.

Thursday’s defeat of the Russians on Snake Island in the Black Sea, where its forces were forced to retreat under sustained Ukrainian bombardment, underlined how much the Russians depended on their superiority in heavy weapons.

The Russian withdrawal from the island was expected to undermine Moscow’s control over vital lanes for shipping grain from Odessa. And when a Russian missile bombed an apartment building and entertainment center near Odessa killing at least 21 people on Friday, Ukrainians viewed it as an act of revenge.

“This was an act of revenge for the successful liberation of Snake Island,” First Deputy Minister of Internal Affairs Yevin Yenin said in an interview. He mocked Russian claims that leaving the island was a “goodwill” gesture.

With its forces expanding, Russia has been trying for months to bolster its defensive positions in the south, as Ukraine recaptured parts of the Kherson region west of the Dnieper River that Russia captured early in the war.

The Ukrainian military said that the Russians had been pushed out of peripheral defensive positions in several locations and that Ukrainian soldiers were operating within 20 miles of Kherson. A senior US defense official said last week that the Ukrainians had not only retaken the villages, but had also demonstrated an ability to hold the land they had retaken.

But military analysts have warned that, despite Ukrainian gains in the south, it is unlikely that they will be able to launch a large-scale offensive and move soon on the city of Kherson, the only regional capital that fell to the Russians.

At the moment, Ukrainian forces are conducting a counterattack on the north and south of the city. At the same time, insurgents inside Kherson intensified their campaign to assassinate Russian proxy leaders and assist the Ukrainian military by engaging in sabotage operations and aiding in shooting at Russian targets.

On Thursday, the Southern Command of the Ukrainian Army said that its forces launched missile and artillery strikes on 150 targets, killing more than 40 Russian soldiers and destroying a group of Russian artillery and armor. The claims cannot be independently confirmed, but data from NASA satellites tracking the fires indicated activity across the Southern Front.