In a nearby classroom some students were singing Christmas carols while Federica Tacconi took notes about some homework at the end of a German lesson.

"Looking through the window I suddenly saw it coming. It was coming slowly, silently, as if it was pushed by the wind, its wings tilting. . . . I was paralyzed by dread. I heard someone screaming, then a rumble and the wall collapsed," she recalled in tears.Federica, 16, is one of the four Italian students of a class of 16 who survived the crash of a flaming military jet into a classroom in a suburban high school Thursday.

Pulled free from the wreckage of a wing, she suffered a crushed pelvis and burns but was not in danger of dying, doctors at Bologna Maggiore hospital said.

Twelve of her classmates were killed instantly when the pilotless jet plowed into a high school at Casalecchio, three miles outside Bologna. The engine had caught fire, forcing the pilot to bail out.

At the time of the crash, 285 students, 28 teachers and four monitors were at the Gaetano Salvemini vocational high school, authorities said.

In nearby classrooms panic spread because of the flames and heavy smoke but many did not immediately realize what had happened.

Many survivors panicked and jumped from the windows before arrival of firemen, a few minutes after the accident.

In total, 87 were injured, including a firefighter and the jet pilot, who bailed out shortly before the crash.

The prosecutor's office and a military commission are investigating the crash. The cause of the engine fire was not immediately known.

Gen. Carlo Brandini said the plane was on a mission to test the effectiveness of an anti-aircraft radar system and had taken off from Villafranca military airport near Verona, 55 miles north of Bologna.

He said the MB-326 Aermacchi was flying at about 280 mph when trouble developed in its single engine, which then burst into flames.

Federica did not know that 12 of her classmates were killed.

"I hope Carmen and Laura managed to jump from the window , or flee through the corridor," she said.

Carmen Schrinzi and Laura Corazza, both 16, were listed among the known victims.