Hundreds of thousands of Russian troops are being mobilized along five lines of attack in Ukraine. Now, it looks like Russia may launch its spring offensive before Ukraine can get Western tanks to the battlefield.

Military officials from Kyiv and the West have been warning of a renewed Russian offensive for months. The latest intelligence shows Russia will keep most of its focus on the industrialized Donetsk region in eastern Ukraine, but Russia also looking to launch new lines of attack to the south near Zaporizhzhia. It’s been six months since Ukraine’s counteroffensive helped it regain wide swaths of territory. Now, the only notable gains on either side came when Russia captured the Soledar, a small mining town about 10 miles from Bakhmut.

Anticipating the arrival of dozens of main battle tanks from the West, Ukrainian troops are now training on those platforms in Europe. The U.K.’s Ministry of Defense said Ukrainian tank crews are adapting quickly to the Challenger 2. Crews will begin training on the German-made Leopard 2 tanks this week.

Tank crews from the Armed Forces of Ukraine have been quick to master the controls of the mighty Challenger 2 this week.

The UK is providing Challenger 2 tanks to Ukraine to help them defend their homeland and retake territory.@DefenceU

🇺🇦 #StandWithUkraine 🇺🇦 pic.twitter.com/iHiOmqR14U

— Ministry of Defence 🇬🇧 (@DefenceHQ) February 4, 2023

Ukraine’s embattled defense minister, Oleksii Reznikov, said even if Russia launches its spring offensive soon, Ukraine has enough soldiers and resources in place to repel such an attack. However, he said ensuring Ukraine’s long-term success will still require more Western weapons – specifically fighter jets.

Air superiority in Ukraine is a vital part of either side’s success. Despite some Western leaders objecting to sending fighter jets to Ukraine, Reznikov said Poland and some Baltic nations will send some aircraft but didn’t say what type or how many.

Reznikov, a lawyer, has been instrumental in securing security aid packages for Ukraine from the West. He’s been so effective that Moscow said it’s essentially now at war with NATO. However, a growing scandal about overpaying for food for troops may force Reznikov out of his position during a critical time in the war.

Russia’s next major offensive is expected to coincide with the one-year anniversary of the start of the war, which is coming up on Feb. 24.

Reuters contributed to this report.