Europe's biggest armed conflict since World War II is poised to enter a new phase in the coming weeks.
With no suggestion of a negotiated end to the 13 months of fighting between Russia and Ukraine, the Ukrainian defence minister said last week that a spring counteroffensive could begin as soon as April.
Kyiv faces a key tactical question: How can the Ukrainian military dislodge Kremlin forces from land they are occupying? Ukrainian President Volodymyr Zelenskyy is working hard to keep his troops, and the general public, motivated for a long fight.
Here's a look at how the fighting has evolved and how the spring campaign might unfold:
HOW DID THE WAR GET HERE?
Russia launched its full-scale invasion of Ukraine on Feb. 24 2022, but its attacks fell short of some main targets and lost momentum by July. Ukrainian counteroffensives took back large areas from August through November.
Then the fighting got bogged down in attritional warfare during the bitter winter and into the muddy, early spring thaw.
Now, Kyiv can take advantage of improved weather to seize the battlefield initiative with new batches of Western weapons, including scores of tanks, and fresh troops trained in the West.
But Russian forces are dug in deep, lying in wait behind minefields and along kilometres (miles) of trenches.
HOW HAS RUSSIA FARED SO FAR?
The war has exposed embarrassing shortcomings in the Kremlin's military prowess.
The battlefield setbacks include Russia's failure to reach Kyiv in the early days of the invasion, its inability to hold some areas and its failure to take the devastated eastern city of Bakhmut despite seven months of fighting. Attempts to break the Ukrainian will to fight, such as relentlessly striking the country's power grid, have failed too.
Moscow's intelligence services badly misjudged Ukraine's resolve and the West's response. The invasion also depleted Russian military resources, triggering difficulties with ammunition supplies, morale and troop numbers.
Russian President Vladimir Putin, apparently concerned that the war could erode public support for his government, has avoided an all-out push for victory through a mandatory mass mobilization.
"The Russians have no end of problems," said James Nixey, director of the Russia and Eurasia program at Chatham House, a think tank in London.
Realizing he cannot win the war any time soon, Putin aims to hunker down and drag out the fighting in the hope that Western support for Kyiv eventually frays, Nixey said.
Russia's strategy is designed around "getting the West to crumble," he said.
WHAT'S NEXT FOR THE UKRAINIANS?
The Ukrainian military starts the season with an influx of powerful weapons.
Germany said this week that it had delivered the 18 Leopard 2 tanks it promised to Ukraine. Poland, Canada and Norway have also handed over their pledged Leopard tanks. British Challenger tanks have arrived too.
Ukraine's defence minister, Oleksii Reznikov, has said he's hopeful Western partners will supply at least two battalions of the German-made Leopard 2s by April. He also expects six or seven battalions of Leopard 1 tanks, with ammunition, from a coalition of countries.
Also pledged are U.S. Abrams tanks and French light tanks, along with Ukraine soldiers recently trained in their use.
The Western help has been vital in strengthening Ukraine's dogged resistance and shaping the course of the war. Zelenskyy recognizes that without U.S. help, his country has no chance to prevail.
The new supplies, including howitzers, anti-tank weapons and 1 million rounds of artillery ammunition, will add more muscle to the Ukraine military and give it a bigger punch.
"Sheer numbers of tanks can drive a deeper wedge into Russian holding positions," Nixey said.
In their counteroffensive, Ukrainian forces will look to break through the land corridor between Russia and the annexed Crimean peninsula, moving from Zaporizhzhia toward Melitopol and the Azov Sea, according to Ukrainian military analyst Oleh Zhdanov.
If successful, the Ukrainians "will split the Russian troops into two halves and cut off supply lines to the units that are located further to the west, in the direction of Crimea," Zhdanov said.
WHAT MIGHT THE END GAME BE?
The Institute for the Study of War, a Washington-based think tank, reckons that Ukraine will need to launch a series of counteroffensives, not just one, to get the upper hand.
The operations would have "the twin aims of persuading Putin to accept a negotiated compromise or of creating military realities sufficiently favourable to Ukraine that Kyiv and its Western allies can then effectively freeze the conflict on their own regardless of Putin's decisions," the institute said in an assessment published this week.
Nixey has no doubt that each side will keep "tearing chunks out of each other" over the coming months in the hope of gaining an advantage at the negotiating table.
A make-or-break period may lie ahead: If Kyiv fails to make progress on the battlefield with its Western-supplied weapons, allies may become reluctant to send it more of the expensive hardware.
The stakes are high: Defeat for Ukraine would "have global ramifications, and there will be no such thing as European security as we (currently) understand it," Nixey said.
------
Associated Press Writer Yuras Karmanau in Tallinn, Estonia, contributed to this report.
