The responsibility of the coordinated bombings in Sri Lanka which killed 321 people and injured about 500 others was claimed by militant Islamic State.
The bombers targeted three churches, 4 hotels and one other place on Easter Sunday.
Churches were bombed during the Easter service whereas two suicide bombers blew themselves up at the luxury Shangri-La Hotel on Colombo’s seafront.
A fourth hotel and a house in a suburb of the capital Colombo were also hit, but it was not immediately clear how those attacks were carried out.
The attacks in the hotels came during the Easter breakfatss when the guests were gathered for buffet breakfasts.
Police had received a tip-off of a possible attack on churches by a little-known domestic Islamist group some 10 days ago, according to a document seen by Reuters.
International anti-terrorism experts said even if a local group had carried out the attacks, it was likely that militant groups Al Qaeda or Islamic State were involved, given the level of sophistication.
“Those that carried out the attack that targeted members of the US-led coalition and Christians in Sri Lanka the day before yesterday are Islamic State group fighters,” said a statement released by IS propaganda agency Amaq said on Tuesday.
The group did not give evidence for its claim.