KYIV, Ukraine — Russian forces claimed some battlefield success Wednesday as Moscow’s invasion of Ukraine labored to gain momentum almost a year after it began , while Ukraine said it needs another few months to stage its own offensive.

The Russian Defense Ministry said its troops broke through two Ukrainian defensive lines in the eastern Luhansk region and pushed back Ukrainian troops some three kilometers (two miles), forcing them to leave behind equipment and the bodies of those killed.

It was not possible to independently verify Moscow's claim. Ukrainian official s made no immediate comment.

Russian artillery, drones and missiles have relentlessly pounded Ukrainian-held areas in the country's east for months, indiscriminately hitting civilian targets and wreaking destruction, as the war largely slowed to a grinding stalemate in the winter. Moscow is hungry for some progress after months of setbacks.

Meanwhile, Ukrainian Defense Minister Oleksiy Reznikov said his country’s forces would need “a few months” to learn how to use new Western weapons before they can try and push the Russians out of Ukraine.

The Donetsk and Luhansk regions, which together make up the industrial Donbas region bordering Russia, continue to bear the brunt of Russia's bombardments as Moscow reportedly moves more troops into the area.

In Luhansk, the number of Russian ground and air attacks is “growing every day,” Gov. Serhii Haidai said on Ukrainian TV.

“The Russians were able to transfer new forces for the offensive and now they are trying to overwhelm us with sheer human mass,” Haidai said.

Donetsk Gov. Pavlo Kyrylenko said Wednesday that one town had come under “nonstop” fire from multiple rocket launchers for over three hours the previous day, damaging at least 12 residential buildings.

At least 12 civilians were wounded when Russian forces struck a five-story apartment block in the city of Pokrovsk, Kyrylenko said. At least two others remained under the rubble.

With the one-year anniversary of Russia’s war approaching, followed by improved spring weather, Western officials and analysts say the fighting could be nearing a critical phase when both sides look to launch offensives.

The Kremlin is striving to secure eastern areas it illegally annexed in September — the Donetsk, Kherson, Luhansk and Zaporizhzhia regions — and where it claims its rule is welcomed. Pro-Moscow separatists have controlled part of Donetsk and neighboring Luhansk province since 2014.

“The enemy, trying to take full control of the Donetsk and Luhansk regions, continues to focus his main efforts on conducting offensive operations in the Kupiansk, Lyman, Bakhmut, Avdiivka and Shakhtarsk areas,” the Ukrainian military reported, referencing towns in the two provinces as well as on the eastern edge of the neighboring Kharkiv region.

Kyiv’s continued defense of Bakhmut , a Donetsk province mining town that for months has been a key target of Russia’s campaign in the east, has been “strategically sound” because it sapped Moscow’s momentum, a U.S. think tank said.

Kyiv’s defense has “degraded significant Russian forces,” including units from the Wagner Group , a Russian private military contractor, the Institute for the Study of War said late Tuesday.

Some analysts had doubted the wisdom of Ukraine holding out in Bakhmut because it could hurt the chances of its expected spring offensive.

On Wednesday, however, the Wagner Group's owner acknowledged in comments to Russian media that it could take weeks for his forces to encircle the city.

Russia’s state RIA Novosti news agency quoted Yevgeny Prigozhin as saying that his personnel might have Bakhmut surrounded in “March-April.”

“Although it is hard to estimate. They (Ukrainian forces) are now getting new types of weapons. (It’s) 100% that we will be destroying these (German-made) Leopard (tanks), 100% that we will figure out how to burn them down. But it is still an important factor,” Prigozhin said.

Prigozhin said though his spokespeople earlier this week that the “toughest battles” were underway north of Bakhmut. His soldiers were storming the area “house by house, square meter by square meter” while the Ukrainian army intensified artillery fire and deployed up to 500 new fighters to the embattled city every day, he said.

Ukrainian officials have not provided details about their troop movements and tactics to defend the city.

Last week, Prigozhin, a millionaire who has close links to Russian President Vladimir Putin and was dubbed “Putin’s chef” for his lucrative Kremlin catering contracts, said that it could take 18 months to two years for Russia to fully secure control of Donbas.

He predicted the war could go on for three years if Moscow decides to capture even more territory east of the Dnieper River.

Prigozhin's remarks represented a rare acknowledgment of the difficulties the Kremlin has faced in eastern Ukraine, where it initially expected its troops to wrap up within weeks after invading the country on Feb, 24, 2022.

Russia suffered a series of humiliating setbacks in the fall when the Ukrainian military launched successful counteroffensives to reclaim broad swaths of territory in the east and the south.

Russian Foreign Minister Sergey Lavrov on Wednesday claimed that Western support for Kyiv’s war effort was prearranged, telling the lower house of Russian parliament that “the U.S. and its satellites are waging a comprehensive hybrid war following years of preparation.”

Lavrov said a revised Russian foreign policy doctrine to be published soon will emphasize the need to “end the Western monopoly on shaping frameworks of international life.”