The Ulster Unionist leader Mr David Trimble said the scenes at the Holy Cross Primary school in Belfast were "appalling and totally unacceptable".
Mr Trimble said there was a serious danger the problems could spread to other schools in the area.
The violence at the school in the Ardoyne area of north Belfast was overshadowing the genuine concerns of Protestants living in interface areas in North Belfast, added Mr Trimble.
"Until violence ends and dialogue begins these concerns cannot be resolved," he said.
He called on the Minister for Social Development to convene a forum for talks talks between interested parties on all the issues concerned - including matters of security, housing and social deprivation.
Earlier today the Catholic Bishop of Down and Connor Dr Patrick Walsh called for an end to the loyalist protest outside Holy Cross Primary School in the Ardoyne area of Belfast.
"The school must be allowed to function properly and then those people in positions of responsibility must be able to come together", he said.
Dr Walsh said he felt a sense of "revulsion" at the violence that has engulfed the area. "I love Belfast and I love the people, but it's just terrible to see parts of Belfast being torn apart at the present time".
He refused to instruct parents to take their children to school via an alternative route, insisting it was their responsibility to ensure a safe passage. "I think the parents themselves must make up their own minds".
Leader of the Church of Ireland Archbishop Dr Robin Eames also urged all sides to try to reach some sort of accommodation.
He said: "No society has the right to deny young children access to education, and it is tragic beyond words to see that the troubles of our community now affect young children of schools in north Belfast".
The scenes of violence at Ardoyne had further damaged Northern Ireland's image, Dr Eames said.
"While I know there are great complexities to this situation, nothing can possibly justify attacks on little children of any denomination".