A police chief has said large protests, whether lawful or unlawful, have "no place" outside primary schools, following recent clashes over the teaching of LGBT lessons.
Chief constable Dave Thompson, of West Midlands Police, said a "number of criminal offences" had taken place outside Anderton Park Primary School in Birmingham since Sunday evening.
The force received reports at 9.30pm on Sunday of assault and criminal damage on Dennis Road, the road in Moseley on which the school is located, as well as reports of malicious communications received by the school on Thursday.
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Anderton Park Primary has been the focal point for protests for more than five weeks.
Police were also present at the school on Monday after protesters claimed about 600 pupils were withdrawn from lessons, while education secretary Damian Hinds has called for more dialogue between schools and parents, saying children and teachers should not have to walk past protests on their way to school.
The force's chief constable has now stepped in to express his "increasing concern" over the rhetoric of the protests.
Mr Thompson said: "In recent months, some Birmingham primary schools have been subject to protests by parents concerning the schools' curriculum on equality.
"These protests have resulted in an ongoing protest outside Anderton Park Primary School. These protests have, to date, been lawful.
"West Midlands Police has been discharging our duty to maintain the public peace and, where criminal offences are identified, to act."
Speaking of the recent clashes between the two sides outside the school, Mr Thompson said: "In the last 24 hours, a number of criminal offences have taken place that the force will investigate and seek to bring people to justice."
Mr Thompson also urged campaigners to consider the effect of their protests on children at the school.
He said: "Frankly, a primary school is no place for the continuance of a large-scale protest, however lawful."
Police and crime commissioner David Jamieson, who supports the work of West Midlands Police, said: "Teachers should be free to get on with teaching a full curriculum that highlights and explains Britain's full diversity, without fear of protests or threats. All forms of equality are equally important.
"As a former headteacher, I understand full well that schools need to work with parents, and would encourage productive dialogue to continue.
"I must emphasise though that protests and threats have no place outside of the school gates, and where there is evidence of criminality, the police will be investigating thoroughly."
Parkfield Community School, also in Birmingham, has also seen protests outside over the teaching of its No Outsiders programme.
Anderton Park does not use this programme or have specific lessons about LGBT.
Earlier this month, the head of Anderton Park, Sarah Hewitt-Clarkson, told Tes that the school was fulfilling its legal duty to teach pupils about equality.