Russia said on Wednesday its troops had broken through two fortified lines of Ukrainian defences on the eastern front, as Kyiv described the situation there as difficult and called for faster military aid ahead of a predicted Russian offensive.

The Russian Defence Ministry said the Ukrainians had retreated in the face of Russian attacks in the Luhansk region, although it provided no details and Reuters was not able to independently verify the battlefield report.

“During the offensive... the Ukrainian troops randomly retreated to a distance of up to 3 km (1.9 miles) from the previously occupied lines,” the ministry said on the Telegram messaging app.

“Even the more fortified second line of defence of the enemy could not hold the breakthrough of the Russian military.”

The ministry did not specify in which part of the Luhansk region the offensive took place. Reuters was not able to independently verify the battlefield report.

President Volodymyr Zelenskiy’s office said Ukrainian forces had repelled some Russian attacks in Luhansk but added: “The situation in the region remains difficult.”

Luhansk regional governor Serhiy Haidai said Russia was pouring heavy equipment and mobilised troops into Luhansk but Ukrainian forces were still defending the region.

“The attacks are coming from different directions in waves,” Haidai said. He added: “Those who spread the information that allegedly our defence forces have pulled back beyond the line of the administrative border (of Luhansk) - this does not correspond to reality.”

The Kremlin has intensified attacks across a swathe of southern and eastern Ukraine in recent weeks, and a major new offensive has been widely anticipated.

Russia’s main effort has been focused on the town of Bakhmut in Donetsk province adjacent to Luhansk.

The General Staff of the Ukrainian Armed Forces did not mention any significant setbacks in Luhansk in its regular morning update. It said Ukrainian units repelled attacks in the areas of more than 20 settlements, including Bakhmut and Vuhledar - a town 150 km (90 miles) southwest of Bakhmut.

Zelenskiy on Tuesday said Russia was in a hurry to achieve as much as it can with its latest push before Ukraine and its allies gather strength.

“That is why speed is of the essence,” he said as NATO defence chiefs met in Brussels for talks that continue on Wednesday. “Speed in everything - adopting decisions, carrying out decisions, shipping supplies, training. Speed saves people’s lives.”

Bakhmut’s capture would give Russia a stepping stone to advance on two bigger cities, Kramatorsk and Sloviansk in Donetsk, giving it momentum after months of setbacks ahead of the February 24 first anniversary of the invasion.

“The battles are literally for every foot of Ukrainian land,” Zelenskiy said, describing the conditions on the eastern frontline in his evening address on Tuesday.

Ukrainian military analyst Oleh Zhdanov said in a YouTube video there was fighting “around every single house” in Bakhmut.