An Islamic cleric in Dublin has urged Muslims to do all they can to identify extremists and their sympathisers.
Shayk Dr Muhammad Umar al-Qadri, who has defied threats from fanatics to condemn the attacks in Manchester, London, Paris and Brussels, warned that Ireland and the EU should now consider deporting the hate-mongers.
The cleric admitted the latest atrocity had left him stunned.
"Absolutely shocked at the attack in Manchester. My heart goes out to all affected.
"May God protect all humanity from the evil of extremism," he said.
He said it was now up to each Muslim in Ireland and Europe to support the fight against terrorism.
"ISIS plans its attacks to create more division and hatred in our societies," he said.
"Terrorism in Islamic costume is not Islamic terrorism. As Muslims we must seize the Islamic costumes from these terrorists.
"May God grant us all the ability to stand united with love and compassion in the face of this terror and eradicate this fanaticism."
Mosques in Dublin, Cork and Belfast have also expressed their solidarity with the victims of the Manchester attack.
"As Muslims we must clean our own backyard by identifying individuals that support the ISIS mentality," Dr al-Qadri added.
"The greatest threat to Islam and humanity comes from ISIS and other such extremist so-called Jihadis.
"Let us unite to get rid of the extremism."
He also warned he would not be intimidated by hate messages posted on social media because of his message of unity.
"Call me a traitor or whatever you want but I will not stop speaking out.
"As Muslims it is our religious obligation to speak out against extremists and support initiatives that aim to eliminate extremism."
Dr al-Qadri helped to establish a special website initiative which aims to help prevent the radicalisation of young Muslims.
The cleric said that Europe needed to get tough with those who promote hate.
"I strongly support legislation that bans hate preachers from entering the European Union and also deports their sympathisers," he said.