Russian forces have made a sudden thrust into eastern Ukraine near the coal mining town of Dobropillia, a move that may be an attempt to increase the pressure on Kyiv to give up land as the US and Russian presidents prepare to meet.
Ukraine's authoritative DeepState war map showed on Tuesday that Russian forces had advanced by at least 10 km (six miles) north in two prongs in recent days, part of their drive to take full control of Ukraine's Donetsk region.
The advance is one of the most dramatic in the last year, although military analysts said the Russians were using small groups of soldiers to try to establish footholds and that it was uncertain if they could maintain their positions in the face of a Ukrainian push back.
DeepState said the Russians had surged forward near three villages on a section of the frontline associated with the Ukrainian towns of Kostyantynivka and Pokrovsk, which Moscow is trying to encircle by exploiting Kyiv's lack of manpower.
"The situation is quite chaotic, as the enemy, having found gaps in the defense, is infiltrating deeper, trying to quickly consolidate and accumulate forces for further advancement," DeepState said on its Telegram channel.
US President Donald Trump and Russian President Vladimir Putin are expected to discuss a possible deal to end the war in Ukraine when they meet in Alaska on Friday. Unconfirmed media reports say Putin has told Trump he wants Ukraine to hand over the part of the Donetsk region that Russia does not control.
The Russian Defense Ministry said units of its army grouping "Center" had improved their positions on the edge of the frontline. Ukraine's military said it was engaged in "difficult" combat near the cities of Pokrovsk and Dobropillia and had sent in reserves to block advances by small groups of Russian troops.
It said some of the groups attempting to bypass Ukraine's defensive lines in the area had already been destroyed, and that others were being engaged by Ukrainian forces.
Pasi Paroinen, a military analyst with the Finland-based Black Bird Group, said the situation had escalated rapidly, with Russian forces infiltrating past Ukrainian lines to a depth of roughly 17 km (10 miles) in the past three days.
"Forwardmost Russian units have reportedly reached the Dobropillia – Kramatorsk road T0514 and Russian infiltration groups have also been reported near Dobropillia proper," he wrote on X.
Pro-Ukrainian open source military analysts were divided on how significant the development was, with some saying that Russia's tactic of sending small groups to quickly seize but not necessarily hold territory for long had made mapping the war much harder.
Konrad Muzyka, director of Rochan Consulting, said the Russian thrust, although it appeared sudden, was the culmination of more than a week of infiltration and positional gains.
RUSSIA MAY GAIN LEVERAGE FOR TRUMP TALKS
Tatarigami_UA, a former Ukrainian army officer whose Frontelligence Insight analysis tracks the conflict, posted: "In both 2014 and 2015, Russia launched major offensives ahead of negotiations to gain leverage. The current situation is serious, but far from the collapse some suggest."
Sergei Markov, a former Kremlin adviser, said the Russians had been able to advance amid "a partial collapse in the front" due to Ukraine's shortage of soldiers.
"This breakthrough is like a gift to Putin and Trump during the negotiations," Markov said, suggesting that, if sustained, it could increase pressure on Kyiv to cede some land to prevent the Russian army eventually taking the rest of Donetsk by force.
To do that, though, Russian forces would first need to take control of Sloviansk, Kramatorsk, Druzhkivka and Kostyantynivka - which Russian military analysts call "fortress cities".
Ukrainian President Volodymyr Zelenskiy has publicly pushed back against the idea of ceding territory to Russia, saying any peace deal must be a just one.
Bohdan Krotevych, former chief of staff of Ukraine's Azov brigade and a National Guard lieutenant colonel, took to X late on Monday to warn Zelenskiy of the threat, saying the frontline in the area was "a complete mess".
"The line of combat engagement as a fixed line does not actually exist," he said.
