In the diplomatic maneuvering over the war in Ukraine, many Ukrainians and their European allies have accused President Trump of offering the Kremlin too many concessions to secure a quick peace deal.

Things look very different from Russia’s bunkers and military hospitals. To many Russian soldiers and their nationalist supporters, the peace proposals from Washington amount to far too little.

Eleven Russian soldiers who are fighting or have fought in Ukraine expressed deep skepticism in interviews of diplomatic efforts that on Friday produced the first direct peace talks in three years, but were brief and yielded little. Speaking by telephone, the soldiers said they rejected an unconditional cease-fire proposed by Ukraine, adding that Russian forces should keep fighting at least until they conquer all of the four southern and eastern Ukrainian regions claimed, but only partly controlled, by the Kremlin.

“We’re all tired, we want to go home. But we want to take all of the regions, so that we don’t have to struggle for them in the future,” said Sergei, a drafted Russian soldier fighting in the eastern Donetsk region, referring to the annexed territory. “Otherwise, have all the guys died in vain?”

The interviews are a rare window into Russian military morale, underlining the domestic challenges President Vladimir V. Putin of Russia would face in ending the war on terms that fall short of his maximalist goals. The soldiers’ demands also suggest that Mr. Putin’s hasty annexation of four Ukrainian regions early in the war may have limited his current options in negotiations because a significant part of the population would view anything less as a defeat.