Police officers have been called to schools in England more than 7,000 times in the past year to deal with violence, according to figures obtained by the Tories.
Shadow children's secretary Michael Gove said the statistics were "very worrying".
The figures were obtained by the Tories under a Freedom of Information request, to which 25 out of 39 English police forces responded.
Each force was asked how many times they were called on to school premises for an attempted or actual violent crime in 2007/08.
The figures revealed that there were 7,311 violent incidents in schools during this time.
The Metropolitan Police were summoned the most, with 2,698 calls, while Thames Valley had 697 calls and Kent had 425.
City of London Police had just one incident.
Mr Gove said: "The number of violent incidents in schools that lead to police being called is very worrying. Teachers, parents and children are all too aware of the threat of violence in schools and the corrosive effect it has on creating a safe learning environment.
"There will always be the odd occasion when teachers need to call on the police for support with a serious incident but at the moment they do not have sufficient powers to nip discipline problems in the bud.
"We want to give teachers more authority to remove disruptive and violent children from the classroom and to tackle problems of bad behaviour before they spiral out of control."
Government figures published last month revealed that thousands of children aged five and under were suspended from schools in England last year for assaulting fellow pupils and teachers.
In total, 580 five-year-olds, 300 four-year-olds and 120 three-year-olds were give fixed-period exclusions for attacking another pupil.
And 10 pupils aged two and under were suspended for physically assaulting another child.
In March, a survey by the Association of Teachers and Lecturers found that one in 10 state school teachers has been injured by a violent pupil.
The union's survey of 800 members across the UK found two-thirds of teachers believed standards of behaviour were getting worse, despite repeated Government crackdowns on poor discipline.
Christine Blower, acting general secretary of the NUT said: "Whilst Michael Gove's initial reading of the figures could look worrying, he should dig deeper into the reasons why schools phone the police.
"An important reason is that police/school liaison has improved tremendously since the problems with security experienced by schools a decade ago. The second is that, as our own survey showed, there are a minority of pupils whose behaviour has become much worse.
"Schools are still one of the safest places for many children. Whilst teachers now have the powers to deal with bad behaviour, it has become a serious matter for wider society that the behaviour of a minority of pupils, and in some cases their parents, have seriously worsened in recent years."
Chris Keates, general secretary of the NASUWT, said: "Any violent incident in schools is, of course, a cause for concern. These figures, however, raise more questions than they answer.
"They are not a complete picture across all police forces and fail to take account of the variations in police response policies.
"The figures do not highlight whether the incidents are pupil on pupil, pupil on teacher, or involve intruders or visitors to the premises.
"It is, therefore, unsafe to draw any firm conclusions from these figures."