As they enter a new phase of warfare centered on tit-for-tat airstrikes across the Russia-Ukraine border, Russia and Ukraine have exchanged rhetoric. Russia promised on Tuesday that its armed forces will use all available means to counter the escalation of Ukrainian bombardment on the border city of Belgorod. Meanwhile, as part of a continuous campaign to get Western allies to increase supplies in light of signs of exhaustion, Ukraine issued a warning that it is running low on anti-aircraft weapons. Russia has returned to a strategy it utilized last winter, when it used air raids to target infrastructure, leaving many Ukrainians without heat and other necessities, as the fight on the front line in eastern Ukraine is mired in trench warfare.