After months of buildup to a campaign that could prove crucial in Kyiv’s bid to reclaim occupied territory, a wave of attacks Thursday focused on the war's southeastern front lines and appeared to represent a significant new push.
Many see this new phase of the war as crucial to persuading Western allies to renew their support as Ukraine grapples with the fallout from the destruction of a critical dam in the region.
Ukraine’s government has consistently said there would be no public announcement of the start of the offensive. The sources spoke on the condition of anonymity to discuss ongoing military operations, while a Ukrainian military spokesman declined to comment.
Russian officials and the country’s cadre of influential military bloggers, who have been sounding the alarm for days, reported a sudden intensification of attacks in the southern Zaporizhzhia region Thursday.
The Russian Defense Ministry said its forces had beaten back a large overnight offensive, inflicting heavy losses.
Ukraine's 47th Mechanized Brigade, with up to 1,500 troops and 150 armored vehicles, "made an attempt to break through" Russian lines, the ministry said in a statement.
NBC News has not verified the claims, and Ukrainian officials did not immediately respond publicly.
The British Defense Ministry said Thursday that “heavy fighting continues along multiple sectors of the front,” and in Zaporizhzhia, Ukraine’s deputy defense minister, Hanna Maliar, said, “The enemy is actively on the defensive.”
Moscow first described a push to break through on the war’s southeastern front lines Monday, claiming its defenses had held firm.
Ukrainian officials denied the claims, accusing Russia of lying and insisting that the long-anticipated offensive was still to come.
The collapse of the Kakhovka dam then delivered a stunning turn that drew attention from the battlefield, forcing thousands to evacuate as floods sweep across the southern war zone.
The destruction could not only do far-reaching damage but also disrupt Ukraine’s military plans.
Zaporizhzhia — one of four partly occupied regions illegally annexed by the Kremlin — has long been seen as most likely a point of a main Ukrainian strike, but Kyiv has seemingly worked to hide its intentions by launching multiple attacks across the vast front lines.
The southern region forms part of the land corridor that the Kremlin fought hard to establish, connecting Ukraine's industrial heartland with the Crimean Peninsula, which Moscow annexed in 2014.
Breaking the land bridge by pushing south toward the coast has been widely seen as most likely a central objective for Kyiv's counteroffensive.
If that is, indeed, the Ukrainian plan, the dam breach may have little impact, Western military analysts said.
"If the Ukrainian plan is to break through RF lines in Zaporizhia and advance to the ground lines of communication from Crimea, or sever the ‘land bridge’ (and I won’t speculate as to what it might be), the resultant flooding is unlikely to impede such an operation," Michael Kofman, the director of Russia studies at the nonprofit CAN research organization in Arlington, Virginia, said on Twitter.
In a further indication that the Zaporizhzhia attack represented a significant new push, it appeared Ukraine for the first time had committed new Western-supplied tanks as part of a heavily armored assault.
The Russian Defense Ministry released video that it said showed its forces targeting a column of Ukrainian vehicles. Michael Horowitz, a geopolitical and security analyst and the head of intelligence at Le Beck consultancy, said in a tweet that the video showed German-made Leopard tanks deployed and at least one seemingly destroyed for the first time in the war.
NBC News has not verified the video.
The Ukrainian counteroffensive follows months when its troops waged a brutal defensive struggle in the eastern city of Bakhmut.
Though Bakhmut was captured last month in a symbolic victory for the Kremlin, Kyiv will hope that its resistance there and weeks of intense strikes behind enemy lines will have worn down Russian forces.
Ukraine's military has been clawing back territory around Bakhmut for weeks and in recent days claimed new momentum in the area.
It was unclear whether the thrust in the eastern Donetsk region was an attempt to draw Russian troops away from Ukraine's main target or a separate effort.
Kyiv's military has been training for months to launch the counteroffensive while amassing billions of dollars in Western military aid to build an arsenal of tanks and long-range rockets.
But the Kremlin has had months to prepare, too, digging trenches and reinforcing its defensive lines across the battlefield.