VIDEO: Russian strike kills 25 as Kremlin to annex Ukraine regions

Russia pounded Ukrainian cities with missiles, rockets and suicide drones, with one strike reported to have killed 25 people, as it moved Friday to annex Ukrainian territory into Russia and put it under the protection of Moscow's nuclear umbrella, opening an internationally condemned phase of the seven-month war.

But even as it prepared to celebrate the incorporation of four occupied Ukrainian regions, the Kremlin was on the verge of another stinging battlefield loss. Russian and Western analysts reported the imminent Ukrainian encirclement of the eastern city of Lyman. Retaking the city could open the path for Ukraine to push deep into one of the regions Russia is absorbing in a move widely condemned as illegal.

The salvos of Russian strikes reported in Ukrainian cities together amounted to the heaviest barrage that Russia has unleashed for weeks. They followed analysts’ warnings that Russian President Vladimir Putin was likely to dip more heavily into his dwindling stocks of precision weapons and step up attacks as part of a strategy to escalate the war to an extent that would shatter Western support for Ukraine.

The Kremlin preceded its scheduled annexation ceremonies Friday with another warning to Ukraine that it shouldn’t fight to take back the four regions. Kremlin spokesman Dmitry Peskov said Moscow would view a Ukrainian attack on the taken territory as an act of aggression against Russia itself.

The annexations are Russia's attempt to set its gains in stone, at least on paper, and scare Ukraine and its Western backers with the prospect of an increasingly escalatory conflict unless they back down - which they show no signs of doing. The Kremlin paved the way for the land-grabs with "referendums,” sometimes at gunpoint, that Ukraine and its Western backers universally dismissed as rigged shams.

"It looks quite pathetic. Ukrainians are doing something, taking steps in the real material world, while the Kremlin is building some kind of a virtual reality, incapable of responding in the real world,” former Kremlin speechwriter turned political analyst Abbas Gallyamov said.

"People understand that the politics is now on the battlefield," he added. "What’s important is who advances and who retreats. In that sense, the Kremlin cannot offer anything сomforting to the Russians.”

A recent Ukrainian counter-offensive backed by Western-supplied weapons has deprived Moscow of mastering its fate on the military fields of battle. Its hold of the Luhansk region appears increasingly shaky, as Ukrainian forces make inroads there, with the pincer assault on Lyman. Ukraine also still has a large foothold in the neighboring Donetsk region.