Police say the death toll in the Easter attacks in Sri Lanka has risen to 359 and more suspects have been arrested.

Police spokesman Ruwan Gunasekara also said on Wednesday morning that 18 suspects were arrested overnight, raising the total detained to 58. The Prime Minister warned on Tuesday that several suspects armed with explosives were still at large.

Another top government official said the suicide bombings at the churches, hotels and other sites were carried out by Islamic fundamentalists in apparent retaliation for the New Zealand mosque massacre last month.

The Islamic State group has claimed responsibility for the Sri Lanka attacks and released images that purported to show the attackers. Prime Minister Ranil Wickremesinghe said that investigators were still determining the extent of the bombers’ foreign links.