A day after Chechen forces virtually ran out of ammunition, Russian planes and artillery unleashed a bitter offensive on Grozny, the capital of the separatist republic. The offensive killed 24 civilians, including a American freelance photographer. Scenes of carnage dotted the city after the first daylight air raid in the civil war -- a sign that Russia is now pushing to end what has become a quagmire. But a speedy end to the fighting would come despite fierce Chechen resistance, overwhelming domestic opposition and turmoil in the Russian military command. Several Russian generals have disobeyed orders or sharply criticized Defense Minister Pavel Grachev's military strategy. (One field commander refused to advance on Grozny or fire on civilians.) Today, according to a Tass report denied by the government, Grachev dismissed three top generals, accepted the resignation of another and took personal command of military operations in Chechnya.