Teachers stage one-day strike over pay
Strike action by some teachers has affected 77 schools in Northern Ireland, the Education Authority has said.
Members of the NASUWT teaching union are staging a one-day strike over pay, job security and workload.
As a result, about a third of schools in Belfast and Newtownabbey have either been closed or partially closed to pupils on Wednesday.
In schools with few NASUWT members, the strike is having little impact.
The education minister called the strike "futile", while the union said it had been "left with no choice".
Education Minister Peter Weir said he had made it clear the education budget was "under severe pressure" and his priority was "protecting school budgets".
"The escalation of this action, resulting in strike days, will severely harm the education of the children that we all seek to serve," he added.
"It will cause major disruption to parents, and put further pressure on other teachers and leaders that are already struggling to cope in addition to damaging the reputation of teachers."
Members of NASUWT are attending a rally in Belfast.
Justin McCamphill, NASUWT's national official in Northern Ireland, said teachers did not take strike action lightly.
"No teacher has any wish to inconvenience parents or disrupt pupils' education, but this action is not the fault of teachers," he said.
"The minister has been given the money to pay teachers the minimum of 1% for 2015-16. It is nothing short of scandalous that he does not think that paying teachers is important."
The union says its members are also protesting about excessive workloads and job insecurity.
In October, all five main teaching unions in Northern Ireland rejected an offer which saw their pay frozen in 2015/16 and a rise of 1% in 2016/17.
NASUWT has previously announced its members elsewhere in Northern Ireland would stage further one-day strikes in January and February.
Meanwhile, the Ulster Teachers' Union, Irish National Teachers' Organisation and Association of Teachers and Lecturers are to ballot their members on 5 December on potential strike action.