COLOGNE -- A 16-year-old girl was on the run in Germany on Monday after apparently trying to set her school on fire with Molotov cocktails and attacking with a knife a pupil who tried to stop her.

The teenager, who has not been officially named, entered her secondary school near Bonn at around 9:00 am (0700 GMT) masked and armed with several knives, an air gun and a rucksack full of bottles of flammable liquid, prosecutors said.

When she then attacked the fellow pupil in the toilets -- half-cutting off her thumb, according to press reports -- the school told police they thought they had a possible school massacre on its hands.

Armed commandos with helmets and flak jackets specially trained to deal with a school massacre rushed to the scene and the 800 pupils were told over the school's loudspeakers to lock the doors and lie on the floor.

"Then the special commandos came and got us out," another pupil, 16-year-old Samuel Weiss, told the Bild daily.

Police found the rucksack but not the girl, who according to local newspaper Express escaped in a Ford Mondeo car.

The paper also named her as Ukrainian national Tanja O. and said she had five kilos (11 pounds) of black powder and had written a farewell letter.

Later the daily said that police were using the teenager's mobile phone signal to track her and that they believed that she was still in the town of Sankt Augustin, 10 kilometers (six miles) east of Bonn.

A spokesman for the prosecutors office said it was "not improbable" that she wanted to commit arson at the grammar school. The injured girl, 17 years old according to Express, was treated in hospital.

The incident came two months to the day after 17-year-old Tim Kretschmer sent shockwaves through Germany when he shot dead nine pupils and three teachers at his old school in Winnenden, and then three passers-by.

Dressed in combat gear and armed with a gun taken from his father's bedroom, Kretschmer went from classroom to classroom expertly picking off his mostly female victims with shots to the head.

He then shot a bystander outside a nearby psychiatric clinic where he had been due to receive treatment, hijacked a car and shot two people at a car dealership before turning the gun on himself in a shootout with police.

The massacre prompted calls to tighten gun laws and ban the kind of violent video games played by Kretschmer. Press reports last week said the government has drawn up new regulations including outlawing paintballing.

The draft law would also bar youths under the age of 18 from shooting high-caliber guns at target practice and permit police to conduct checks at the homes of gun owners to ensure their weapons are under lock and key.