Both sides appear ready for an enduring conflict on Europe's eastern fringe.
With Russian President Vladimir Putin's invasion of Ukraine entering its twelfth week, experts agree with Western officials that he is committed to a long-lasting and widespread war with Kyiv.
Ukrainian officials are increasingly confident that they will be able to withstand Russian attacks, backed by billions of dollars in aid and weaponry from NATO allies.
The Director of National Intelligence Avril Haines said on Tuesday that Putin was ready for a prolonged conflict in Ukraine that would extend well beyond the eastern Donbas region, where Russia's advances have stalled in recent weeks.
Ukrainian Foreign Minister Dmytro Kuleba warned Moscow that his country's war aims had grown since the outbreak of hostilities, as Ukrainian troops retook several villages around the city of Kharkiv.
Vladislav Zubok, a professor of international history at the London School of Economics, said that after being convinced of Ukraine's defensive capabilities, NATO allies were determined to help it hold out and put an end to Russian incursions in Eastern Europe.
It is now more complex than just killing two sides, he said. The war is regional, but the complexity is European and international, and the U.S. poses as a senior patron of Ukraine, determined not to let it lose. Speaker Nancy Pelosi said that the aid would help Ukraine defend its nation, but also its democracy for the world, because of the additional $40 billion in aid that was authorized by the House on Tuesday. In his most strident communication so far, Kuleba suggested that Kyiv s military goals had changed from attempting to reclaim territory seized by Russia this year to reclaiming all territory Russia has occupied since 2014.
He said that the picture of a Ukrainian victory was an evolving concept. If we are strong enough on the military front and win the battle for Donbas, the victory for us in this war will be the liberation of the rest of our territories, Kuleba told The Financial Times.
While he didn't mention the Crimean Peninsula specifically, the chief diplomat expressed his desire to defeat Russia's Black Sea fleet and unblock the passage. Dan Hamilton, senior nonresident fellow at the Washington-based Brookings Institution, said it was premature to talk of a wide-ranging Ukrainian counteroffensive despite recent local gains.
As of February 24th, Russian separatist entities had about a third of the Donbas under control. The Russians now control about 80 percent of the Russians, he said.
Hamilton said neither side would accept a political settlement that included conceding Ukrainian territory seized by Russia, so both armies were forced to dig in and fight.
I don't think the Ukrainians have the capacity without much more serious support, and that will take some time, he said. We can hope for a disputed line of control and a cease-fire. The conflict has killed thousands of Ukrainian civilians and forced 13 million people from their homes.
Zubov said Kyiv's victory aims, at least in the public, needed to be commensurate with the loss and suffering the public has so far had to bear.
He warned that expanding territorial goals beyond regions seized since February 24 could have the negative effect of galvanizing Russian support for an even deadlier conflict.
If the Ukrainians were to push the message about retaking Crimea, that would be impermissible, he said. It would cause Putin to announce a mobilization and escalate the war.