The attacks were an onslaught against the entire humanity and not just against the Sri Lankan people, S M Backer, the leader of the city headquartered ITJ said.
The attacks unleashed on Easter Sunday, observed as a holy event by Christians, could be only construed "as a well planned and coordinated terror attack," he said in a statement.
Expressing his condolences, Backer expressed solidarity with the families of the victims and said he prayed to the Almighty for peace.
"The heinous attack in which hundreds, including children and women were killed makes one shudder...whatever form terror may take; be it religion, race, or language, it should be defeated," he added.
The perpetrators of the dastardly attack should be brought to book and they must be given maximum punishment and it should be carried out in the public.
"The forces behind the attack should be identified and the Srilankan government should ensure that investigating agencies zeroed in on the real culprits," he said.
He appealed to the Sri Lankans to maintain calm in these "grievous times and not give room for rumours and lend a helping hand to the affected people."
The series of blasts that tore through churches and luxury hotels on Easter Sunday killed 290 people, including eight Indian nationals and left more than 500 injured.
No group has claimed responsibility for the attacks.