Fighting is currently raging near Avdiivka in the Donetsk region as Moscow tries to take advantage before Western aid arrives.
ADVERTISEMENTRussia's army has made notable advances in eastern Ukraine.
In its daily intelligence update on Tuesday, the Institute for the Study of War (ISW) said Moscow's army had gained ground in Ocheretyne near Avdiivka in the eastern Donetsk region.
Footage posted by pro-Kremlin military bloggers shows a Russian flag flying above the wrecked village, amid reports that Russian troops had advanced some 5 km in 10 days.
The ISW said Moscow's forces did not have full control of the area, however.
According to the US think tank, the situation on the frontline will "likely continue to deteriorate... particularly if Russian forces increase their attacks to take advantage of the limited window before the arrival of new US aid."
Ukrainian military chiefs estimate that up to 25,000 Russian troops are trying to storm Chasiv Yar and surrounding settlements in the Donetsk region.
They are attempting to capture the village of Ivanovskoye and the outskirts of Bogdanovka to break through to Chasiv Yar.
Chasiv Yar is a crucial strategic point for further advances toward Kostiantynivka, Kramatorsk and Sloviansk - three cities in Donetsk.
The Pentagon is poised to send $1 billion (€0.93 billion) in new military aid to Ukraine, US officials said on Tuesday.
Meanwhile, the UK also announced €580 million in new military support for Kyiv and Lithuania said it had transferreda batch of M577 command and staff armoured vehicles to Ukraine.
The announcements follow concern by analysts that delays in Western security assistance have helped Russia's offensive, with the ISW saying in February that Kyiv had to conserve military material.
Some US military aid for Ukraine is already in Germany and Poland, reducing the time needed for the weapons and equipment to reach the front, CNN reported.
Still, there are concerns.
"Even if US materiel moves quickly, transport logistics will likely mean the aid 'will not begin to affect the situation on the front line for several weeks,' the ISW wrote on X on Tuesday.
On Tuesday, Russian Defense Minister Shoigu said the Moscow army would increase the intensity of attacks on logistics centres and storage bases for Western weapons in Ukraine in response to the US aid bill.
In February, Ukrainian forces withdrew from Avdiivka, claiming a lack of artillery shells and air defence systems from the West limited the ability of Ukrainian troops to defend themselves against Russian advances.
Since Russia’s February 2022 invasion of Ukraine, Washington has sent more than $44 billion (€41 billion) worth of weapons, maintenance, training and spare parts to Ukraine.
For the bulk of that time, aid packages were moving routinely every few weeks.
ADVERTISEMENTBut the money started to dry up by the end of the fiscal year on 30 September.
By mid-December, the Pentagon said it had run out of money and had to stop sending weapons because, without the funding package stalled in Congress, it could no longer afford to replace them.