KYIV, Ukraine (AP) – Ukrainian forces have encircled Russian troops in the strategic eastern city of Lyman in a counteroffensive that has humiliated the Kremlin. Russian bombardments, meanwhile, are intensifying after Moscow illegally annexed a swath of Ukrainian territory Friday in a sharp escalation of the war. In the northeast, Ukrainian officials accused Russian forces of attacking a civilian evacuation convoy, killing 20 people including children. In the south, Ukraine’s nuclear power provider said Saturday that Russian forces blindfolded and detained the head of Europe’s largest nuclear plant. The fighting comes at a pivotal moment in Russian President Vladimir Putin’s war. Putin this week heightened his threats of nuclear force and used his most aggressive, anti-Western rhetoric to date.