Almost half of Scottish councils have seen a rise in assaults on teachers by pupils in the last three years, according to new figures.

Fourteen of the country's 32 councils reported an increase between 2011/12 and 2013/14.

Ten councils saw the number of assaults drop in that period, according to figures obtained by the Scottish Conservatives following a freedom of information request.

Overall, there were 1,879 incidents in 2013/14, which was down on 2012/13 but 16% higher than 2011/12.

Staff reported being subjected to physical attacks such as punching, kicking, pushing and shoving, and also verbal assaults.

In the last year, one teacher reported having a stone thrown at their head, while others reported being kicked, pushed and spat on.

Scottish Conservative young people spokeswoman Liz Smith MSP said: "It's absolutely right that a zero-tolerance approach to this sort of behaviour is taken in schools.

"Teachers should not be subjected to any form of assault, no matter how minor it may appear. It just should not happen.

"It's important therefore to make sure teachers feel empowered to take the necessary action and, where necessary, head teachers should not shy away from expelling pupils who are persistent, serious trouble-makers and who are preventing others from getting on in the classroom.

"We shouldn't demonise pupils, but it is nevertheless vital that teachers do not feel threatened in their own work environment.

"We therefore need to look at putting more preventative strategies in place to deal with any pupils who demonstrates a pattern of abusive behaviour towards teaching staff and other pupils."

Larry Flanagan, general secretary of teaching union the Educational Institute of Scotland (EIS), said: "Any rise in reported assaults is obviously a matter for concern. While we know the majority of incidents that occur in our schools are low-level in nature, there are a number of incidents of a more serious nature involving violence, threat of violence or intimidation.

"Although these remain a very small percentage of cases, the EIS is very clear that a zero-tolerance approach should be taken to such events, including police involvement where violence has been used or threatened. There is no circumstance where it is acceptable for any employee, including a teacher, to feel physically threatened in the workplace.

"Young people, children, who become involved in such behaviour should be supported in addressing their actions but, for example, we cannot have a situation where a teacher has been assaulted and the pupil responsible is not removed from that school register, as has happened in some areas.

"It is vital, however, that the response to all incidents is measured and appropriate. Local authorities will always want to take the necessary steps to ensure that our schools are as safe as possible, without damaging the open and welcoming environment that our schools seek to provide."

A Cosla spokesman said: "The bottom line is that violence in Scotland's schools is both rare and always unacceptable. Scotland's councils take the safety of their pupils and staff very seriously and all have policy procedures in place to record every incident of violence within schools and all such recorded incidents are swiftly dealt with in the appropriate manner.

"The vast majority of pupils in Scotland's schools are well behaved and permanent exclusion should always be the last resort."

Renfrewshire Council reported the highest number of incidents in 2013/14, with 277 assaults made on staff, while Stirling and the Western Isles reported one each.

The other eight Scottish councils either did not respond to the freedom of information request or did not provide full figures.

A Renfrewshire Council spokesman said: "These figures don't give an accurate reflection of the position in Renfrewshire compared to other local authorities.

"We do all we can to minimise attacks and to protect and support our employees and this approach means we encourage our employees to report all types of incidents.

"The bulk of these figures refer to verbal aggression or confrontation and not physical attacks. They also apply to all employees within the school and not just teachers. However we take all incidents extremely seriously and we work hard to reduce the number of violent incidents against our employees.

"We put a lot of work into supporting youngsters to change their behaviour. This includes working with parents. But where an incident merits an exclusion we are prepared to use that option."

The Renfrewshire Council total for the freedom of information request includes all aggressive behaviour against all employees within schools, giving a total of 277 incidents.

The number of incidents just involving teachers was 183. Out of these, 126 incidents were verbal, including refusing to follow an instruction by a teacher which leaves 57 incidents.