By Pavel Polityuk
KYIV (Reuters) - Russia said on Wednesday it had broken through two of Ukraine's fortified defence lines in the east and Kyiv spoke of relentless Russian attacks making it "difficult for us", as Western allies announced more military aid for Kyiv including artillery rounds.
Bolstered by tens of thousands of reservists drafted in December after months of humiliating battlefield reverses, Russia has intensified attacks across southern and eastern Ukraine in recent weeks, and a major new offensive is widely anticipated as the first anniversary of its invasion nears.
The Russian Defence Ministry said Ukrainian forces had retreated in the face of Russian attacks in the Luhansk region, although it gave no details and Reuters was not able to independently verify this and other battlefield reports.
"During the offensive ... the Ukrainian troops randomly retreated to a distance of up to 3 km (2 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.
Later in the day, Ukrainian deputy defence minister Hanna Malyar said Russian forces were mounting "round-the-clock" assaults on government positions, without specifying where.
"The situation is tense. Yes, it is difficult for us. But our fighters are not allowing the enemy to achieve their goals and are inflicting very serious losses," Maltyar wrote on the Telegram messaging app.
Luhansk regional governor Serhiy Haidai said Russia was pouring heavy equipment and mobilised troops into Luhansk.
"The attacks are coming in waves from different directions. (But) those who spread the information that allegedly our defence forces have pulled back beyond the line of the administrative boundary (of Luhansk) - this does not correspond to reality."
In Kyiv, the capital's military administration said six Russian balloons that may have contained reconnaissance equipment were shot down over the city on Wednesday after air raid sirens blared.
"The purpose of launching the balloons was possibly to detect and exhaust our air defences," it said on the Telegram messaging app. Russia did not immediately comment.
RUSSIAN ONSLAUGHT ON BAKHMUT
Russia is also waging an artillery and ground onslaught on the city of Bakhmut in Donetsk province adjacent to Luhansk.
Serhiy Cherevatyi, spokesperson for Ukraine's eastern military command, told Ukrainian TV on Wednesday that fierce battles were being fought in Bakhmut, widely flattened by months of bombardment that has turned it into a virtual ghost town.
Bakhmut's capture would give Russia a stepping stone to advance on two bigger cities, Kramatorsk and Sloviansk further west in Donetsk, which would revive Moscow's momentum ahead of the Feb. 24 first anniversary of the invasion.
Zelenskiy said on Tuesday Russia was in a hurry to achieve as much as it could with its latest push before Ukraine, armed with heavier and longer-range firepower from the West, gathers strength for what many expect to be a spring counter-offensive.
Ukraine is using shells faster than the West can make them and says it needs fighter jets and long-range missiles to counter the Russian offensive and recapture lost territory.
'GRINDING WAR OF ATTRITION'
NATO Secretary General Jens Stoltenberg said alliance members were increasing production of 155mm artillery rounds and needed to ramp that up even further to help Ukraine. It was "obvious" NATO states had to spend more on defence, he added.
"So yes, things are happening but we need to continue, we need to step up even more. This is now becoming a grinding war of attrition and (this) is a war of logistics," he told reporters after a meeting of NATO defence ministers in Brussels.
European Union foreign policy chief Josep Borrell urged countries to join Germany in sending "as many tanks as possible, and as quickly as possible" to Ukraine after media reports that Denmark and the Netherlands said they would not deliver Leopard 2 battle tanks like Berlin.
"It would be very disappointing if, after so long of pointing the finger at Germany for not doing anything, these countries now don't follow suit," Borrell told Germany's Phoenix broadcaster.
"I know there are hundreds of tanks in EU armies, some of them need to be refurbished, but then you have to do it, and do it quickly, because in the spring it will be too late."
U.S. Defense Secretary Lloyd Austin said after the Brussels talks that Ukraine had a very good chance of taking and "exploiting" the initiative on the battlefield this year.
Austin said that for every new system NATO provides Kyiv, it will train troops on it. "We're laser-focused on making sure that we provide a capability and not just the platform."
Britain said it and other European nations would provide military equipment including spare parts for tanks and artillery ammunition to Ukraine via an international fund, with an initial package worth more than $241 million.
On Jan. 20, a senior U.S. administration official said Washington was advising Ukraine to hold off with a major offensive until the latest supply of U.S. weaponry is in place and training has been provided.
Russia calls the invasion a "special military operation" against security threats, saying NATO shows hostility to Russia daily and is growing more involved in the conflict. Kyiv and its allies call Russia's actions an unprovoked land grab.
Russia holds tracts of Ukraine's southern regions of Kherson and Zaporizhzhia, including its nuclear plant, nearly all of Luhansk and over half of Donetsk. Last year, Russia declared it had annexed the four regions in a move condemned by most United Nations members as illegal.