Paris Terror Attacks: Religious leaders condemn the barbarism of Isil's twisted faith
Prayers were said in churches across the country on Sunday for those killed and injured in the Paris terror attacks.
The Catholic Primate, Archbishop Eamon Martin, said the "horrific events challenge us to pray and work even more earnestly for an end to the evil of terrorism everywhere".
In Dublin, Archbishop Diarmuid Martin warned of an "horrific example of what fundamentalism can do and what happens when religion is distorted for ideological reasons".
Pope Francis said extremists were attempting to justify violence using the name of God.
Bishop Noel Treanor, in St John's Parish, Belfast said that his prayers were with those who were killed, their families and friends, those who were injured and the people of France.
He called on all religions to promote and inculcate, at individual and local community level, attitudes which "pursue the way of peace over war and violence". He urged people to reject the "words of poisonous hatred and xenophobia".
In Sligo, Bishop Kevin Doran told Mass-goers that for the people of Paris it must have seemed that the end of the world had come.
"For many of them, indeed, it was the end of their life on earth. For many more, it was the undermining of their confidence in civilised society and of their ability to trust in the goodness of their fellow human being.
"Anyone with his or her eyes open can see that our world is caught up in an ongoing struggle between good and evil."
Islamic organisations in Ireland jointly condemned "the heinous attacks".
Shaykh Dr Umar Al-Qadri, Imam of the Al-Mustafa Islamic Centre and chair of the Irish Muslim Peace and Integration Council, said in a video message: "We, people of faith and people of no faith, must come together to unite against extremism, to unite against these enemies of mankind.
"Let us all unite for peace against these terrorists."