A top Belfast grammar school has pledged to immediately remove sectarian graffiti said to have remained on a door for weeks.
Photographs emerged of the slogan`KAT' - meaning `Kill All Taigs' - apparently taken inside the main building of the Royal Belfast Academical Institution (RBAI) at College Square East in the city centre.
A caller to The Irish News claimed the graffiti had been there for at least a month, despite a school inspection taking place in February.
The door is believed to be on an upper floor of the building on a busy thoroughfare passed by pupils and staff every day.
The caller described it as "raw hatred" and said they found it "intimidating, threatening and offensive".
"Schools should have a zero tolerance of bigotry and sectarianism. Hatred holds back change and keeps people from working together.
"Schools have a primary responsibility to educate children about tolerance and respect of other religious or political traditions. I have serious concerns as to why the graffiti was not removed immediately".
When contacted by The Irish News, school principal Janet Williamson said the graffiti would be removed immediately.
"The Royal Belfast Academical Institution is a multi-cultural integrated school which does not tolerate any form of discrimination including sectarianism," she said.
"Having brought the matter of graffiti to our attention, we will have it removed with immediate effect."
Sinn Fein MLA Barry McElduff, former chairman of the assembly education committee, described such graffiti as "alarming".
"Schools must, of necessity, be welcoming spaces for everyone," he said.
"I welcome the fact that when the school authorities were contacted, they gave an undertaking to have it removed immediately".
A spokeswoman for the Education and Training Inspectorate (ETI) said it did not comment on individual schools.
"Complaints about any form of graffiti should, in the first instance, be raised directly with the school. The ETI can, however, confirm that the Royal Belfast Academical Institution was inspected on February 6 2017".
