An 18-year-old student armed with an axe has been arrested in Germany after throwing petrol bombs into two classrooms at his school.

Twp girls were seriously injured before police shot the student in the stomach to stop him.

One girl is in a critical condition in hospital with head injuries while another was severely burned by one of the petrol bombs.

The 18-year-old was armed with two knives and several petrol bombs when police cornered him inside the Carolinum secondary school in the southern town of Ansbach.

He was shot several times and arrested, Bavarian Interior Minister Joachim Herrmann said.

The student remains in a critical condition.

Police said they had no idea what had motivated the young man, who had never aroused suspicion, to attack his fellow students.

The incident is the latest in a spate of school attacks in Germany. In March, a 17-year old killed 15 people in a shooting spree at his former school in the southwest town of Winnenden before killing himself.

In 2006, a masked man armed with rifles and explosives attacked a school in the western town of Emsdetten, wounding 11 people before killing himself.

Germany suffered its worst school shooting in April 2002 when a gunman killed 17 people, including himself, at a high school in the eastern city of Erfurt.

Mr Herrmann said Bavarian police had been able to react quickly and effectively after studying the Winnenden attack and had reached the school several minutes after an alarm was raised.