COLOMBO: Nine suicide bombers, including a woman, were involved in the massive Easter Sunday bombings in which over 350 people were killed, PTI reported quoting a top police officer on Wednesday. Police Spokesman Ruwan Gunasekara said that out of the nine suicide bombers, eight have been identified by the Criminal Investigation Department (CID). The ninth bomber was confirmed as the wife of one of the suicide bombers, he said.

Meanwhile, 60 people have been arrested for possible links to the multiple attacks carried out on Easter Sunday. Of them, 32 are in custody with the CID. All of those arrested are of Sri Lankan nationality, Gunasekara said.

The Islamic State terror group has claimed the attack, although it did not provide direct evidence of its involvement.

The state minister of defence Ruwan Wijewardena said the multiple bomb attacks were carried out not by the National Tawheed Jamath (NTJ) but by its splinter group. Sri Lanka's government had earlier blamed the blasts on the NTJ.

Wijewardena said there was no evidence at present whether the splinter group had any foreign connections.

Wijewardena told reporters that the members of the group had differences and the final attack was carried out by a group that left the main NTJ.

The death toll has jumped to 359 on Wednesday, up from a previous count of 321 people. Nearly 500 people have been injured in the attack.

Ten Indian nationals have been confirmed dead.

State defense minister Wijewardene said the majority of Sunday's suicide bombers were from well-heeled families. They were also well-educated, including at least university graduate who had studied abroad.

"Most of them are well-educated, and come from maybe middle- or upper-middle-class. So they are financially quite independent and their families are quite stable financially," he said.

Wijewardene said, "We believe that one of the suicide bombers studied in the UK and maybe later on did his post-graduate in Australia, before coming back to settle in Sri Lanka."

The number of foreign nationals who have been identified as killed is 34. Additionally, 14 foreign nationals are unaccounted for at present, and could be among the unidentified victims at the Colombo Judicial Medical Officer's mortuary, officials said.