KYIV — Russia intensified its spring offensive across Ukraine's front line in early March, with Russian forces capturing 12 settlements while suffering more than 8,710 casualties in one week, according to Ukraine's commander in chief. Gen. Valery Gerasimov said his troops were on the offensive across the entire front line.

Gen. Valery Gerasimov said his troops had taken 12 Ukrainian settlements in the first two weeks of March.

The Institute for the Study of War said the reported Russian casualty rate during the spring offensive was unsustainable given Russia's current recruitment rates. The institute said the unsustainable casualty rate would likely degrade Russia's ability to wage large assaults in the mid- to long-term.

The Institute for the Study of War said it remains unlikely this year that Russian forces will seize the so-called Fortress Belt, the main fortified defensive line in the eastern Donetsk region, with Moscow likely to make some tactical gains at substantial cost. Russia's full-scale invasion of Ukraine has been ongoing for four years.

"We see that the peace process is deadlocked. Russia is asking for what we can't give it — our land," said Oleksandr, a lieutenant. Ukraine holds land in the Donetsk region that Kyiv refused to cede in exchange for peace, and that land is central to a stalemate in negotiations.

Russian President Vladimir Putin said he would seize Donetsk by force and take full control of the Donbas region if diplomatic efforts fail. "As long as they push, we will kill them," Oleksandr said.

Russia and Ukraine do not regularly report the number of their own dead, wounded, or missing in the war. The Russian Defense Ministry released footage showing a Russian soldier firing artillery toward a Ukrainian position.

"While Ukraine remains under sustained pressure, its battlefield performance demonstrates that its forces continue to be resilient and adaptive, capable of conducting successful local counterattacks and of leveraging new technologies and methods, especially in realms such as drones and artificial intelligence, to offset their numerical inferiority," said Christopher Tuck, a conflict and security expert at King's College London. "Overall, this has allowed Russia to retain the initiative in some areas, but it absolutely has not established for Putin an irreversible path to victory."