A "HATE campaign" against the Muslim community in Ireland is being investigated by gardai.
It has emerged that mosques and schools have received anonymous letters containing violent threats against Muslims living here.
Justice Minister Alan Shatter condemned the hate mail and revealed he had brought the matter to the attention of Garda Commissioner Martin Callinan for appropriate action.
"I utterly condemn racism and religious bigotry in all of their forms and am appalled by the nature of these communications. Religious intolerance has no place in our society. Incitement to hatred and incitement to violence are offences under our laws," Mr Shatter said.
The Immigrant Council of Ireland said that letters with "direct threats" had been sent in the post and placed on the internet, and it urged that anyone responsible for threats against the Muslim community should be prosecuted.
Denise Charlton, the chief executive of the Immigrant Council, said: "The emergence of this letter and its threats is both sinister and alarming. The language used is that more associated with right-wing extremists which have re-emerged in other parts of Europe."
She said that the council became aware of this "hate campaign" after being contacted by concerned members of the public. It had now established that the contents of the letter have also been placed online, including on an international anti-Islamic website.
The response to this incident will test the effectiveness of Ireland's incitement to hatred legislation, Ms Charlton added.
The Irish Anti-War movement (IAWM) revealed that mosques and Muslim schools had received the "threatening letters".
"Some Muslim girls have reported they got similar letters referring to their hijabs, that came through their letterboxes at their homes," said Jim Roche of the IAWM.
He said the language contained in the letter was "intimidating and extremely violent" and makes a specific reference to the planned construction of a mosque in north Dublin.
The body has described the letter as "unspeakably shameful and disgusting".
A garda spokesperson confirmed that gardai in Donnybrook are investigating a letter sent to the Clonskeagh mosque. Dr Ali Selim, of the Clonskeagh Mosque and Islamic Cultural Centre, told the Irish Independent that there were two letters sent to the mosque, one last week, and one this week.
He said that the writer was "ignorant of reality" because "more than half of the Muslim community in Ireland, estimated to be 65,000, are Irish either by birth or by naturalisation. So they are at home".