Death toll rises to 359 in Lanka bombings, 18 more arrested

The death toll from the Easter suicide bombings in Sri Lanka rose to 359 and 18 more suspects were arrested, police said on Wednesday, report agencies.

The Islamic State group has claimed responsibility and released images that purported to show the seven bombers who blew themselves up at three churches and three hotels on Sunday in the worst violence this South Asian island nation has seen since its civil war ended a decade ago.

Sri Lankan President Maithripala Sirisena has asked the police chief and defence secretary to quit following the Easter Sunday suicide bomb attacks as warnings before the bombings went unheeded.

President Maithripala Sirisena's office announced that he asked for the resignations on Wednesday.

It wasn't immediately clear who would replace them.

Sirisena said during a televised speech on Tuesday that he planned to change the head of the defense forces within 24 hours.

The government has said the attacks were carried out by Islamic fundamentalists in apparent retaliation for the New Zealand mosque massacre last month but has said the seven bombers were all Sri Lankan. Prime Minister Ranil Wickremesinghe said investigators were still working to determine the extent of the bombers' foreign links.

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

Sri Lankan authorities have blamed a local extremist group, National Towheed Jamaar, whose leader, alternately known as Mohammed Zahran or Zahran Hashmi, became known to Muslim leaders three years ago for his incendiary speeches online.

The IS group's Aamaq news agency released an image purported to show the leader of the attackers, standing amid seven others whose faces are covered. The group did not provide any other evidence for its claim, and the identities of those depicted in the image were not independently verified.

The office of New Zealand Prime Minister Jacinda Ardern issued a statement responding to the Christchurch claim that described Sri Lanka's investigation as "in its early stages."

"New Zealand has not yet seen any intelligence upon which such an assessment might be based," it said. An Australian white supremacist, Brenton Harrison Tarrant, was arrested in the Christchurch shootings.

Word from international intelligence agencies that National Towheed Jamaar was planning attacks apparently didn't reach the prime minister's office until after the massacre, exposing continuing turmoil in Sri Lanka's government.