Ukrainian President Volodymyr Zelensky has urged allies to be speedy in sending more military help as NATO defence ministers met and Russia bombarded the eastern front line in what appeared to be the early salvo of a new offensive.

Much of Russia’s artillery fire was focused on Bakhmut, a bombed-out city in Donetsk province and a principal target for President Vladimir Putin. Ukrainian troops there have fortified positions in anticipation of street fighting.

Bakhmut’s capture would provide a stepping stone for Russia to advance on two bigger Donetsk cities, Kramatorsk and Sloviansk, and give Moscow momentum after months of battlefield setbacks following its invasion last February.

NATO defence ministers met in Brussels on Tuesday to discuss the war and stockpiles. Mr Zelensky said Russia was in a hurry to achieve as much as it could with its latest push before Ukraine and its allies could gather strength.

“That is why speed is of the essence,” he said in an evening video address.

“Speed in everything – adopting decisions, carrying out decisions, shipping supplies, training. Speed saves people’s lives, speed brings back security, and I thank all our partners who realise that speed is important.”

Ukraine is using shells faster than the West can make them.

US Defence Secretary Lloyd Austin said he expected Ukraine to launch its own offensive against Russia in the spring and Kyiv’s allies were working to ensure they had the armour, firepower and logistics to make it effective.

“Ukraine has urgent requirements to help it meet this crucial moment in the course of the war. We believe there’ll be a window of opportunity for them to exercise initiative,” Defence Secretary Austin told the meeting of defence ministers.

NATO Chief Jens Stoltenberg said Mr Putin was “preparing for more war, for new offensives and new attacks”.

With the first anniversary of Russia’s invasion nearing, the Kremlin has intensified operations across a broad swathe of southern and eastern Ukraine, and a major new offensive has been widely anticipated.

In its evening report, the General Staff of the Ukrainian Armed Forces said Russian forces trained mortar and artillery fire on more than 20 towns and villages in the Bakhmut part of the front line, including the city itself.

They also launched missile strikes on the industrial cities Kostyantynivka and Kramatorsk in Donetsk, it said.

Russian forces had made incremental progress in their assault on Bahkmut, White House spokesperson John Kirby said.

Promised battle tanks last month, Ukraine is also desperate for fighter jets and longer-range missiles to nip any significant new Russian offensive in the bud and help turn the tide against Moscow’s far superior firepower.

The Kremlin, which calls the invasion a “special military operation” to eliminate security threats, said NATO was demonstrating its hostility towards Russia every day and was becoming more and more involved in the conflict.

Kyiv and its allies call Russia’s actions an unprovoked land grab.

Ukrainian officials also said the Russians had suffered big losses around Vuhledar, a town 150 kilometres south-west of Bakhmut, including tanks, armoured vehicles and personnel.

Reuters was unable to independently verify battlefield reports.

On the snowbound Ukrainian front line between Vuhledar and Marinka 30km to the northeast, and 400 metres from Russian positions, two officers said Kyiv’s forces were holding firm against intensifying Russian artillery and mortar fire.

Russia holds swathes of the southern regions of Kherson and Zaporizhzhia, including its nuclear plant, nearly all of Luhansk and over half of Donetsk, including the regional capital.

A US-backed report published on Tuesday said Russia has held at least 6000 Ukrainian children – likely many more – in sites in Crimea and Russia whose primary purpose appears to be political re-education.

Russia’s embassy in Washington did not immediately respond to a request for comment.

– AAP